EAS Newsletter for March 2021

Welcome to the March newsletter.

Little did we think that when we decided to produce a newsletter for last April, that we’d still be doing it a year later. Given the Prime Ministers aspirations published yesterday [Monday 22nd February], it looks unlikely that we’ll be back in the Museum before May at the earliest. Even then, I suspect some members may not be willing to attend Kendal Museum for meetings. I also suspect that speakers before the summer will either be unable or unwilling to travel. For example, universities currently have their hands full trying to deliver courses and they will probably not quickly remove the current staff travel ban. Obviously, the Committee will just follow the guidance and we’ll inform you about what is happening through either this august publication or by email.

The recent astronomical news, quite rightly, has been dominated by Mars and the successful Perseverance landing. The landing video, do I need to say more, is extraordinary and well worth watching if you haven’t already seen it. But Perseverance wasn’t the only arrival at Mars as there were orbiters from both the Chinese and UAE too. The Chinese probe has a small rover too. The reason all three arrived at a similar time is simply due to orbital mechanics. More from David on these later.

I guess this is time for my frequent moan at the lack of clear skies in Cumbria… it certainly hasn’t been great this past month with only the odd short break. It was even cloudy at full moon! Mind you, the forecasts haven’t been accurate either as I found two clear nights mid-month [10th & 11th] which weren’t forecast to be – that makes planning and preparation difficult.

Last spring/summer we were rewarded with the first decent naked eye comet for quite some while – Comet NEOWISE C/2020 F3. For some stunning images, including something called the sodium tail, which I admit I’d never heard of, have a look at this link.

Sadly, no more naked eye comets are due for a bit although one, COMET LEONARD C/2021 A1, is possible low in the northern sky during early December. We’ll just have to see.

Don’t forget that at the end of the month, Sunday 28th March, the clocks change as we revert to summer time.

So, keep safe and don’t forget our upcoming meeting on March 4th – with Megan Argo from UCLAN on the Square Kilometre Array.

Clear skies.

SpaceX launch site – Ian Bradley

You’ve probably seen the iconic photographs of the two SpaceX spaceships SN9 and SN10 both sat together on the launchpad prior to the launch of SN9. I thought it might be useful to see the launch site to give a bit more context to David’s excellent reports. The assembly and control centre is a around 3km away from the launch site.

SN9 and SN10 with Starhopper on the right Credit: SpaceX.

They looked quite close together, and although they are quite large at 50m tall and 9m diameter, they do seem quite close to one another and the landing zone. Having seen SN8 have a RUD (Rapid Unscheduled Disassembly or in English, a destructive crash landing) on the failed landing attempt, I wondered at the possibility of the crash debris damaging the other rocket… so I looked for some aerial photos…

The launch complex. Credit: RGV Aerial Photography

To give an idea of scale in the first photograph, the distance from the left-hand edge of the construction site to the wall on the right of the tank farm is approximately 500m so the centre of the landing pad is about 200m from the launch test stands. They really are surprisingly close together. I guess that shows the confidence of SpaceX in their engineering and design. The second image, which must be a slightly earlier image, shows SN9 and SN10 on their launch test stands and the landing pad behind with what I presume is the remaining debris on the pad from SN8. Clearly the pad was damaged by the crash landing and was then undergoing repair

SN9 and SN10 with debris from SN8 on the damaged landing pad behind. Credit: RGV Aerial Photography

Astronomy News – David Glass & Richard Rae

Hope

On 9/2/21, the Hope probe from the United Arab Emirates successfully completed its braking manoeuvre and entered the orbit of Mars. The probe will study the upper Martian atmosphere, with the aim of discovering why Mars lost its water around 3 billion years ago and is now so cold and dry. It will look at how particles are being lost from the planet and escape into space and how the upper atmosphere interacts with the atmospheric layers below. The Martian atmosphere is tenuous and much thinner than the atmosphere that we enjoy here on Earth. Initially the UAE programme is destined to last 2 years and we should get some excellent photographs from its advanced Hi-Res camera. The probe was launched by Japan, is managed by the UAE and has collaborations with United States Universities – a truly international effort.

Here is a video (just over a minute long) revealing the rationale behind the mission.

The image below contains more on the probe…

Schematic of the Hope probe (credit: https://www.planetary.org/space-missions/uae-hope)

And here’s one of the first images to be returned from Hope…

full-disc image of Mars from the Hope spacecraft (altitude 24,700km). (Credit: UAESA/MBRSC/LASP/EMM-EXI)

Hope’s research aims build upon NASA`s MAVEN (Mars Atmosphere and Volatile Evolution Mission) mission, which was dedicated to researching the upper atmosphere of Mars and determining the importance of the role a planet’s magnetic field plays in the retention of an atmosphere. Hope, however, will be at a much higher orbit (22,000 – 44,000km) instead of MAVEN`s 4,500 to 150km. MAVEN has been in orbit since 2014, and has painstakingly created a map of electric current systems (interaction of charged particles in the atmosphere and the solar wind). For more details, MAVEN’s home page is here. Some very interesting information on mapping electric currents, and the importance of the planet’s magnetic field in regulating climate and retaining water can be found here (~4 minutes)

Tianwen-1

Impression of Tianwen-1’s rover after deployment. (credit: CCTV/China National Space Administration)

The Tianwen-1 spacecraft successfully entered the orbit of Mars on 18/2/21. Richard Rae mentioned this ambitious Chinese mission in a talk to EAS last year and you may remember it comprises 3-parts – an orbiter, a lander and a rover. If successfully deployed, this will be an engineering first for remote planetary exploration, whereby the three components are contained within one payload at launch.

Tianwen-1 means “questions to heaven” and China will become the second nation to operate a rover on the planet’s surface. The craft is currently able to collect information on potential landing sites in the Utopia Planitia region. Here is an inspiring video of Tianwen-1 during February`s orbital capture from space.com. The landing containing the rover is expected to occur in May or June of this year. The rover carries scientific payloads to investigate the minerals on the Martian surface as well as a ground penetrating radar to detect ice deposits.

Here is a (1 minute video) representation of how everything should go from space.com. This is a pathfinder mission for the Chinese exploration of Mars as there are plans for future mission to retrieve Martian samples and bring them back to Earth by 2030.

Perseverance

Few of us can have missed the spectacular landing of the new Perseverance rover on Mars on 18/2/21 – or the equally spectacular coverage of the event, and the initial images and videos released afterwards which really highlighted the technology at work. So, I won’t dwell on it here. If you want to watch it again, highlights and video footage released post-landing are here.  Raw images from the rover are coming in, and can be found at here.

A typical shot from the right Mastcam-Z on the Perseverance rover on Mars (credit: NASA/JPL-Caltech/ASU

Stuart Atkinson does an excellent job of processing these images to bring out the best in them – check out his Facebook page “Postcards from Perseverance”. 

SpaceX

After the successful test firings of the engines on Starship SN9, we just had to wait until it was launched up to an altitude of a few kilometres and brought safely back. They got part of it right.

SpaceX never seem to announce when tests and launches are going to happen (please put me right if they do!), so the only way to find out is to check with online resources frequently. SpaceX’s Twitter feed can be of use, but it can also be very informative to use Labpadre’s or NASASpaceflight’s live streams on YouTube. I check the LabPadre feeds daily. On 2/2/21 I found that the SN9 launch was imminent, so throughout the afternoon I kept checking, but not a lot seemed to be happening so I parked it. Then by chance I checked the SpaceX twitter feed that evening, and found a live feed with a countdown – 1 minute 30 seconds to go! Here are some of the live images from LabPadre’s Nerdle Cam that I screen grabbed after a panic rush to grab the laptop. The test didn’t quite go to plan…

Launch – looking good!

Five minutes later. Er…should it be coming in on its back?? Nope.

(all images credit: LabPadre)

Fireball from the liquid methane tank, oxygen tank detached and failed separately (right of image). Jet- propelled debris from the non-burning release is apparent – look closely in both images! Something is skating along the ground in the right-hand image.

During the flight, the Twitter live feed showed a large stream of cryogenic vapour coming out of the back of the rocket, which might have been unignited fuel/oxygen/both. Without sufficient engine power and the ability to steer properly, a crash was inevitable.

The only thing to do after an event like that is to try again. SN10 is in position, and is now getting ready to fly. The first test firing of its engines was on 23/2/21, after which one of the engines was replaced. The second test firing was on 25/2/21…  (sound available!).

So, we now wait for readiness to launch of SN10, which hopefully will be soon (but we’ve said that before and it’s taken ages!).

Shortly after the SN9 flight, SN7.2 (a lightweight cryogenic liquid storage tank for use in future Starships was pressure tested on 4/2/21. It did fail (see image), but at least the test will have helped to establish the limits for operation.

SN7.2 under test – large leak is apparent to the right (credit: LabPadre).

Golf on the Moon…

I tried pitch-and-putt once. I declared myself dangerous, and consequently I’ve never developed an interest in golf. However, this is a moment where golf was out of this world. Alan Shepard was commander of the Apollo 14 mission in early February 1971 (50 years ago!), and took with him a specially-designed golf club head that would fit on a lunar sampling tool. On 6/2/71 he took two one-handed shots from the Moon’s surface. The second one apparently went “miles and miles and miles”…

Andy Saunders, an image specialist who specialises in re-mastering Apollo images, has analysed photos and images of the event from the astronauts’ cameras, a camera on the Lunar Module and images from the Lunar Reconnaissance Orbiter. Features are apparent on the Lunar surface from this classic experiment…

Traces of the golf shots taken on the lunar surface – divots and balls. (credit: NASA/JSC/ASU/Andy Saunders)

 

Scaled image showing the features and distances for the golf shots. (credit: NASA/JSC/ASU/Andy Saunders).

The maximum distance travelled for the second ball was about 40 yards – and there’s no blaming a gopher that picked up the ball and ran back with it. The challenge for future visitors is to do better!

Celestial Selfies – James Robertson

How many images of the night skies have been taken? Millions probably, adding up everything from backyard astronomers to professional observatories. This article turns this on its head.

The one object we don’t think of imaging at night is Planet Earth, not least because we can’t beyond our terrestrial horizons. Yet humans have launched satellites and probes into the solar system and beyond, bearing cameras. They are our selfie sticks. They photograph us and our world.

This article presents a selection of visually great and also significant images together with their history. It follows on from the February Newsletter where Graham Fell recollected the 2013 photo of Earth taken by Voyager with at least members of EAS waving back at it.

It all started with this, Photo 1, the first image of Earth taken from space, in October 1946. The camera was on board a V2 rocket captured by the Americans from the Germans at the end of WW2. The warhead was replaced with scientific instruments and a 35mm cine camera taking one frame every few seconds.

The photo here was taken from a height of 105km, considerably beating the previous altitude record of 22km in a balloon flight. The camera was destroyed in the crash landing on return but the film survived in a sturdy steel case.

Photo 1: V2 rocket view of Earth from 105km

All image credits are NASA.

At the time the V2 image must have seemed remarkable. Today it looks pretty tame through eyes accustomed to the Hubble Space Telescope images. A more modern equivalent of the V2 cloudscape nevertheless does pack a punch. This shot (Photo 2) from May 2011 of clouds from orbit was the first picture taken of a Space Shuttle attached to the International Space Station and gives a good indication of its scale. It was taken from the Soyuz capsule being used to bring astronauts home. The thin blue envelope of the atmosphere shows clearly at the edge of the planet and the floating structure of the ISS is still novel. We see a lot of images shot from the ISS but not many of the outside detail.

The image was not released for some weeks after being taken. The camera’s SD card was left on board the Soyuz craft. At least they got it back, which is more than they did with the V2s. Sixty-four V2s were launched between 1946 and 1952 taking photos of the Earth. A lot of cameras got trashed.

Photo 2: ISS in orbit over clouds

For something iconic featuring the Earth, we have to go back some decades to the Apollo lunar missions. This image (Photo 3) was taken from the Apollo 8 Moon orbit on Christmas Eve 1968 by astronaut Bill Anders. For many at the time, and even now, the pure beauty of the planet and the contrasting desolation of the lunar surface was a haunting sight. Phases of the Earth are still an unexpected sight too.

Photo 3: Apollo 8 view of Earth

The patterns of clouds on these Apollo images have been compared to those taken on the same date from Earth orbit satellites, identical, in an effort to debunk the claim that the Moon landings were faked in a Hollywood studio. But you can’t convince some people. No doubt the satellite images were all faked as well in Photoshop.

Kennedy said in his 1962 speech that the goal was to land a man on the Moon and return him safely. A lot was riding on this as well as on accomplishing it within the decade as promised.

Photo 4 shows the ascent of the Lunar Module (LM) about to reunite with the Command and Service Module (CSM). It is a photograph that very nearly didn’t get taken. Things had not gone to plan. The connection between the CSM and LM was not fully depressurised and the LM got an extra impetus from escaping air when disconnected. Armstrong reckoned it would send the LM past the planned landing point by 3 miles. Then two alarms registered computer processing overload, the second being a Master Alarm that set off a klaxon. Aldrin later described it as what you got in a Dive, dive, dive scene in a submarine movie (this sort of thing ).

Armstrong switched to manual control at about 500 feet. Although Aldrin was designated Pilot for the LM his role was not to fly it as such but be Chief Engineer. Much of the descent was computer controlled and any human intervention was Armstrong’s job as Commander. The manual controls were on the left side of the LM looking outwards where Armstrong stood, and the LM was too small in any case for the two astronauts to swap places quickly. Armstrong got the LM down with just 18 seconds of fuel to spare, four miles past target, and with the LM sliding several feet sideways on the lunar surface on contact. Renowned for his ultra-coolness in actual emergencies, Armstrong’s heart rate nevertheless doubled to hit 156 per minute by the time the Eagle had landed.

The photo illustrates a key accomplishment of the Apollo 11 astronauts, at a finalising point in the mission – getting there, completing the exploration, getting off the Moon in one piece and preparing to dock with the CSM, with home in sight. It was taken by Michael Collins on the CSM on 21 July 1969. Though not the mission Commander, it was his job to fly the CSM for real rather than Armstrong. Soberingly, he was the pilot trained to be able to return home solo if the other two astronauts were killed outright or stranded on the Moon

Photo 4: Apollo 11 Lunar Module Eagle returns from lunar surface, destination Earth

HG Wells began War of the Worlds with these words: ‘No one would have believed in the last years of the nineteenth century that this world was being watched keenly and closely by intelligences greater than man’s.’[end Quote]

What might the Martians have seen? With the help of an increasingly long selfie stick we now know (Photo 5). This is a milestone image of the Earth, the first taken from the surface of another planet. Curiosity sent it back on 31 January 2014. It provokes the question: Will there ever be a moment when a human born on Mars looks up at a bright star that is Earth, and wonders what it’s like, never having been there?

Photo 5: Earth from the surface of Mars]

The next two selfies were taken on the same day, 29 July 2013, but from different directions. The first image (Photo 6) shows Earth and Moon viewed from Mercury, captured by a Messenger probe looking for moons of Mercury. Pluto is said to be in the field of view, but is far too small to show up. The distorted shapes are due to overexposure. It’s arguably not packing the visual punch of some of the other selfies. But taken from a distance of 98 million km by a robotic spacecraft that got there safely, achieved orbit, took images and successfully transmitted the data back home, it sums up how much a species of tree dwelling primates had evolved to aspire to and then achieve.

Photo 6: Earth and Moon from Mercury Messenger

From the other side of Earth orbit, the Cassini probe imaged us as described in the February ’21 Newsletter. This (Photo 7) is another from the sequence of images, with a close up of the rings and with the Moon recorded as well but not visible here. It was taken from the impressive distance of 1.5 billion km. Carl Sagan, the planetary scientist, populariser of astronomy, cosmologist, pondered on these images and our true significance. He saw them as transcending all our earthly preoccupations, the Earth floating as a speck in an infinite Cosmos. He called it a very small stage in a vast arena.

Photo 7: Earth from Saturn’s rings

Carl Sagan was also involved with the final selfie for this article. Voyager 1 was by this time heading to the fringes of the Solar System. He strongly advocated capturing a view of Earth, from what was a record distance away, at approximately 6.4 billion kilometres. NASA was unsure, concerned that sunlight even at that range might burn out the camera (as had happened on the Apollo 12 mission).

In the end, a wide-angle image of the sun was taken using the darkest on-board camera filter with the shortest possible exposure. The results have been presented by NASA first as a mosaic of the wide angle shot and two narrow angle colour frames (Photo 8), containing Earth and Venus. They are in the correct place in the image and taken using three coloured filters (at less than 1 second exposure each). There doesn’t seem to be a version actually showing the planets. The alternative highly processed version (Photo 9) does show Earth, coincidentally in a shaft of sunlight scattered off the Voyager camera shading.

Photos 8 & 9: Earth from the greatest distance ever.

Carl Sagan made a renowned poetic speech about the blue dot of Earth, so easily masked by a mote of dust on a computer screen. Sagan died in December 1996 but left a recording of his 4-minute speech available here.

This is the concluding line, fitting at a time of pandemic and growing urgency about global warming:

“[This distant image of our tiny world] … to me, it underscores our responsibility to deal more kindly with one another and cherish the pale blue dot, the only home we’ve ever known”

Carl Sagan 1994

Recent Photos

NGC2264, the Cone Nebula and Christmas Tree cluster in the constellation of Monocerous. The Fox Fur Nebula just right of the bright star at the top.

Two-panel mosaic imaged from Kendal over the nights of February 10th & 11th using a Skywatcher 10″ Newtonian, and a QHY163m mono camera with Hα and OIII filters. Total exposure time over 7 hours.

M42 and M43 in Orion with NGC1977, The Running Man Nebula, above..

Two-panel mosaic imaged from Kendal over the nights of January 30th and February 10th using a Skywatcher 10″ Newtonian, and a QHY163m mono camera with Ha and OIII filters. Even with 30 second exposures, the core of M42 is blown out!.

EAS Newsletter for February 2021

Welcome to the February newsletter.

Cumbrian clouds and rain have lived up to their reputation the past month with very few clear evenings. Just glimpses every now and again. I guess the forecast for the next month is more of the same! My fault as I’ve acquired some narrowband filters and a mono-astrocamera!

Last month, we had an excellent talk by Prof. Lionel Wilson on Venusian vulcanology continuing the series on volcanos of the Solar System. Hopefully, we’ll get Lionel back for another talk in the next year or so, as he himself said, there are other volcanic systems out there… Thinking of the programme, David Glass has done an excellent job on the programme for our 1st Thursday of the month meetings for the rest of the year.

So hopefully we’ll have some good meetings and with luck and a vaccine, maybe even back in Kendal Museum.

Don’t forgot that the Cumbria Dark Skies Festival starts shortly (Feb 5th to 21st) with many interesting online talks (many only £3.50). Further information can be found here.

A lot of this is being driven by Friends of the Lake District (FoLD) as part of their dark sky initiative. EAS is involved with FoLD, mainly Clive and I, in their Dark Skies project as are many other Cumbrian astronomy societies. There are things we as individuals can do to reduce light pollution (LP) and protect our darkish skies – see here for a few tips. If you see any excessive light source in the Kendal area, for example through bad positioning, angling or just on all the time, let me know and I will pass that information on to the FoLD team. They are currently employing consultants to do an LP survey before they tackle individuals or companies to try and get some changes. The ‘Environmental Act 1990; law on statutory nuisance’ covers LP nuisance, so things can change.

One final note on LP. There is a lady in Penrith (which has no astro society) trying to get light glare reduced. LP is surprisingly bad round Penrith with some big industrial sites by the M6, several brightly lit quarries and nearby Center Parcs. She was unsure how to go about getting LP reduced and various local societies (Cockermouth, Carlisle, EAS) had a Zoom discussion with her. The bottom line was that ultimately, locals have to drive change. Since then, I’ve had a few email exchanges with her. She has written to the local paper (The Cumberland and Westmorland Herald). This produced supportive replies from locals and I contacted the paper and sent them an image of light pollution over Penrith taken from Orton Fell. However, being a realist, it is difficult for us as a society to do much, being Kendal based, but if you happen to live in that direction, are affected by LP and willing to talk to her, I’m happy to put you in touch.

Clear Skies

Ian Bradley, on behalf of the EAS committee

Perseverance Mars rover landing – Ian Bradley

Click images to ‘enbiggen’.

Don’t forget that NASA’s ‘Perseverance’ Mars rover is due to land on Mars on Thursday, February 18th at about 20:55 GMT in Jezero Crater after another ‘7-minutes of terror’; entry, parachute descent followed by the final sky crane lower onto the surface. NASA TV is live from 19:15 GMT. There’s a nice animation here. Here’s hoping for another successful landing. As John McNamee, project manager for the Mars 2020 Perseverance rover mission puts it, “Don’t let anybody tell you different – landing on Mars is hard to do.” With luck, we’ll soon get an image like this on the right which I believe was the first mastcam image taken by Curiosity inside Gale Crater.

Why Jezero Crater? On ancient Mars, water carved channels and transported sediments to form fans and deltas within lake basins. Images suggest that the 750km diameter Jezero Crater in the Isidia Planitia region was at one time filled with water forming a shallow lake. It is believed that such a wet region could have been environmentally favourable to life. A river flowed into this lake off nearby highlands, dumping eroded material to form a delta. The landing site in Jezero Crater was chosen to be near this delta because orbital spectral data show that some of the sediments here have minerals that indicate chemical alteration by water – clays and carbonates. A great place to fulfil the Mars 2020 mission’s science goal of studying a potentially habitable environment that may still preserve signs of past life.

Here’s hoping.

Astronomy News – David Glass

SpaceX

The much-anticipated test flight of Starship SN9 mentioned in the December newsletter looked like it would go ahead early in January. It didn’t, but it is now likely on 1st – 3rd February. Anyone checking in on the webcam sites around Boca Chica would have seen lots of activity in the run-up to this, and several reasons are behind the delays including technical issues, poor weather and bureaucracy.

SN9’s Raptor engines were test-fired initially on 6/1/21, followed by an astounding three static fires with no intervention on 13/1/21 (18:28, 20:22, 21:36 GMT). There’s a great compilation video of this event.

SN9’s three static firings on 13/1/21 (credit: NASASpaceflight.com/bocachicagal)

After all this testing, two of the Raptor engines needed to be replaced because of minor damage. There was another static firing on 21/1/21 and 22/1/21 GMT, and a “wet dress rehearsal” for launch 28/1/21, with delays to launch due to adverse weather and other issues. Since then, SN9 has been sitting on the pad awaiting FAA approval for launch after a regulatory hold-up prevented a launch on the 28th.

The issue which caused Starship SN8 to crash is believed to be low fuel tank pressure during the latter stages of the flight. The solution to this for SN9 is to pad the tank with helium, which will help to maintain the tank pressure as it is emptied during flight. However, this is only a temporary fix while other permanent solutions which add less mass are explored. Another item of interest was pressure-tested at the site on 26/1/21. A new fuel storage vessel, named Starship 7.2, has been built out of thinner (and therefore much lighter) stainless steel plate. This was filled and pressurised with liquid nitrogen, and held at pressure for 3.5 minutes. The test was judged to be a success, and the vessel didn’t burst dramatically like its predecessors. The new design represents a significant saving in mass, which means more payload can be carried.

Starship SN7.2 under test (credit: LabPadre)

And within the last few days, Starship SN10 was moved into position for testing and launch…

Through the fog, SN10 (right) in position for testing etc at Boca Chica, with SN9 on the left (credit:LabPadre)

Blue Origin

Blue Origin’s New Shepard launch vehicle is intended to transport payloads to sub-orbital altitudes (i.e. into space and straight back down again) – including scientific instruments and paying passengers. An impressive test (no 14) of the vehicle and a new 6-seat passenger capsule was conducted on 14/1/21, from their West Texas launch site. The capsule includes large windows to allow great views for the passengers (referred to as astronauts – well technically they are!), and a new feature which allows the whole assembly to rotate slowly to give everyone the best views was demonstrated during the flight.

The test was successful, with the capsule separating from the launch vehicle and reaching an altitude of just over 66 miles (351,000 ft approx.). The launch vehicle then did a successful powered landing, and the capsule landed later on its parachutes with impact cushioned by retro-rockets. There was one passenger on board, “Mannequin Skywalker” who is a veteran of these test flights, and additional cargo of 50,000 postcards from students around the world. Highlights of the flight are here.

If that has inspired you to buy a ticket for this 11-minute flight with forces of up to 3g and a few minutes in microgravity with stunning views, take a look here.

New Shepard flight test no. 14 (credit: Blue Origin)

NASA SLS

NASA’s Space Launch System (SLS) was put in place on its test facility at Stennis Space Center near Bay St. Louis, Mississippi towards the end of 2020. After a “wet” dress rehearsal in December, the time came for a static fire test of its four RS-25 engines (last used on the space shuttles) on 16/1/21. This was due to last for around 8 minutes, which is the full duration of a launch. However, certain safety parameters were set conservatively and the test was aborted after about a minute. In spite of this, a huge amount of data was gathered on the performance of the system which will guide future tests. SLS will eventually be used for the Artemis 1 mission which is heading for the Moon.

The test itself was particularly impressive, with high-resolution cameras giving views from many different perspectives. The whole live stream is available here (2h 20 min!), but I recommend that you skip to 2h 00min to get the build-up before the test and the test itself. Note the dramatic use of water (>300,000 US gallons/min) to quench the exhaust, which really gives a feel for the power involved. funniest live comment: “Shut up about SpaceX!

NASA SLS hot test fire (credit: NASA Stennis Space Center)

Virgin Orbit

At the other end of the scale for rockets, Virgin Orbit successfully put 10 small satellites into low-Earth orbit using its LauncherOne system on 17/1/21. This is a converted Boeing 747 (in Virgin livery) which took the rocket up to 35,000ft altitude before releasing it to fly into space. This system has the advantage that it can be deployed from anywhere that has the right runway length and facilities. I won’t discuss the ethics of small satellites in orbit, especially involving an aforementioned operator.

Virgin Orbit’s LauncherOne deploying a rocket to orbit (Credit: Virgin Orbit)

Photosynthesis on Exoplanets?

We all know that photosynthesis, where complex molecules are built up from simple ones using sunlight and chlorophyll, is essential for life on this planet. With the discovery of exoplanets around red dwarf stars in the right orbits for liquid water to exist, a logical question is whether the spectrum from these stars could sustain photosynthesis as we understand it. A paper released on ArXiv in January suggests that it can.

The figure below shows the spectra of the Sun and different types of red dwarf star. It’s clear that the spectra of the red dwarfs all peak at longer wavelengths, i.e. would appear redder to the human eye. The research team reproduced this spectrum and the intensity of light expected on exoplanets that could potentially support life, and subjected different types of extremophile cyanobacteria to it. One (Chlorogloeopsis fritschii PCC 6912) can survive in hyper-salty lakes and very hot thermal springs. Another (Chroococcidiopsis thermalis PCC 7203) is found in a wide range of hot/cold and wet/dry environments. A third (Synechococcus sp. PCC 7335) was originally isolated from a snail shell found in an inter-tidal zone, and can withstand changes in light levels as well as wet and dry conditions. A fourth (Synechocystis sp. PCC 6803) was not expected to photosynthesise under these conditions and was used as a control.

Spectra of the Sun and red dwarf stars, from yellow to near infra-red (Claudi et al. 2021)

The results? PCC6803 and 7203 were able to photosynthesise. PCC6912 and 7335 (the control) were just about able to photosynthesise, using the low levels of light that they required at wavelengths away from the spectral peaks. This is because the more capable bacteria use particular types of chlorophyll that can make use of the light wavelengths available.

This does offer the potential for biological process that we understand to be present on habitable exoplanets around red dwarf stars. If chlorophyll (or something like it) is involved in these processes, then perhaps ways of detecting such activity could be devised. For example, deficiency at the right wavelengths in the reflected spectra from these exoplanets could be due to absorption of light by chlorophyll. This is a challenge for the extremely large telescopes being built or planned – watch this space! The ArXiv paper is here.

Waving at Saturn in 2013 – Graham Fell

The image is an early one of Saturn taken by Hubble. A few years ago, NASA sent a probe to Saturn called Cassini and it sent back some fantastic images over a period of several years. Google Saturn Cassini images and you will find images that are truly wonderful and are Art in their own way.

The greatest picture taken by Cassini was taken from the other side of Saturn looking back towards the Sun, with Saturn blocking out the Sun, and Earth as a single blue pixel in between the rings. Here it is, a genuine untouched real photo.

Now NASA told us exactly when this would happen and so it was that many people waved at Saturn at the moment the picture was taken. So, I (and many others) are in that pixel! Google “Waving at Saturn”, click on images and the third image is taken from Kendal Castle and the idiot at the back in shorts and a silly hat is me!

If any of you use the Helme Chase Surgery on Burton Road, then you may know Carol in the pinkish red sweater at the front. She is a nurse there.

Bearing in mind that (obviously) there was no-one aboard Cassini, I find it amazing that the NASA scientists could work out that picture and then get Cassini to be in the right place at the right time! Kendal was one of the few places in the UK that decided to “Wave at Saturn” and there were about 400 locals that went up to the Castle to witness it. I am immortalised forever in that picture and my naked legs will still be visible long after I disappear off this planet. It was July 19th 2013.

This was a moment for the Society to be proud of and was one of many outdoor events organised by Stuart Atkinson in the earlier days of the Society.

Recent Photos

The Andromeda Nebula M31 from Kendal. Taken with a tracked 200mm telephoto lens – 36 x 3 minutes exposures.

The Pleiades M45 from Kendal. Taken with a tracked 200mm telephoto lens – 25 x 3 minutes exposures.

A rather serendipitous observation whilst checking the focus on a camera. Uranus was well placed and… to my surprise I could see three ‘star-like’ objects round the planet and yes, some of them were the moons. Oberon, Titania and Ariel were visible plus a star. Ariel is almost lost in the glare, just a slight blip partially separated, from Uranus. There are another two brightish moons completely lost in that glare.

 

A quick telephoto shot of the Moon – January 22nd – before the clouds rolled in again.

   

EAS Newsletter for January 2021

Welcome to the January newsletter.

Unfortunately, covid regulations are still in force so our meetings have to continue by Zoom. The newsletters will continue and it would be nice to get some contributions from you. David and Richard have worked hard to provide news updates. Moira has been providing regular ‘Constellations of the Month’. So many thanks to all of you.

Our next meeting, the Annual General Meeting will be later this week, so please join in and let us hear your views. That, hopefully short, discussion and votes, will be followed by the concluding talk from Lionel Wilson on the geology of our Solar System; having covered both the Moon and Mars in previous talks, Lionel will this time concentrate on Venus, what when I was nowt but a lad, was referred to as Earth’s twin. We’ve come a long way since then with multiple spacecraft visits.

The skies in December didn’t play fair again giving only fleeting glimpses of the conjunction of Jupiter and Saturn. The best night round here was possibly the 12th but there was a later chance at the end of the month. I spent a rather cold early evening dodging hail and heavy rain at Helsington on the 20th but I probably left home just a few minutes too late – story of my life? I hope some of you got better views.

Clear skies.

Ian Bradley, on behalf of the EAS committee

Astronomy Links

Astronomy Links We’ve circulated this by email before

  • Gresham College free Astronomy lecture series by Professors Katherine Blundell and Roberto Trotta. See the Gresham College site and have a look for these and other events. Not all of these are on astronomy.

Astronomy News – David Glass

SpaceX

There was a notable success for Starship SN8 early in December. It was scheduled for a flight to about 15km altitude, a controlled descent in a horizontal position, a flip to vertical and a safe landing. Well, most of it happened on 9/12/20, after a previous attempt that was aborted 1 second before launch.

SN8 was fitted with three raptor engines for this exercise. Preparations for launch suffered one pause at about 2 minutes before launch, but after that all went to plan and the launch went ahead! Here are two different views of SN8 shortly before launch:


SN8 just prior to launch on 9/12/20. Left: A view of the three Raptor engines during cryogenic cooldown, just before
launch (credit: SpaceX). Right: Venting place towards the end of fuel tank filling. (Credit: Labpadre).

The flight itself was spectacular, and you can see it here (~8 min long)

All was going very well, and it was particularly impressive to see the Raptor engines being adjusted to control orientation. Also impressive was the gradual transition to horizontal, the “glide” down and the final flip to vertical using two of the engines. At this point there is no impression of speed towards the ground, until the ground came into view – then, it was apparent that the craft wasn’t vertical and was coming in too fast. The result was a classic boiling liquid expanding vapour explosion (BLEVE, pronounced “blevy”) as the pressurised fuel was released suddenly, ignited and formed the classic fireball.

In spite of the dramatic end, the flight was a success and many important principles for these starships were tested. The cause of the crash has been discussed as low fuel tank pressures, which can be corrected in future starships (maybe by vaporising a bit more stored fuel to keep the pressure up).

Next up is SN9, which suffered a bit of a mishap during construction when it collapsed in the assembly bay a day or so after the SN8 launch….


SN9 taking a rest. (Credit: Twitter/Bocachicagal)

However, a quick look at a live camera today shows SN9 in place on a launch pad at Boca Chica:


Starship SN9 in place on Test Stand 2 (TS2), 1/1/21. Credit: Labpadre

There will be the usual pressure testing of the fuel tanks (warm and cold) and test firing of the Raptor engines, before another flight hopefully in a few weeks. Looking forward to it!

Hyabusa-2

Back in November 2018 we had a talk about the Hyabusa-2 spacecraft, which subsequently managed a successful rendezvous with an asteroid (Ryugu) and grabbed samples of material from its surface and below for return to Earth. During December there was some excellent news about this mission – the samples were successfully returned to Earth as planned and have been retrieved! The sample return module created a nice fireball effect in the sky and then landed with a parachute near Woomera in South Australia…


The Hyabusa-2 sample return container, back safe on 5/12/20. (Credit: JAXA/EPA)

Anyone who has seen the excellent 1971 film The Andromeda Strain might have been a bit worried at this point, but all went very well. Later, the capsule was found to contain material from the asteroid and a gas sample:


Material from Ryugu sampled by Hyabusa-2. (Credit: JAXA)

Analysis of this material will provide information on the material around during the earliest days of the Solar system, and will help to improve understanding of how our system formed. Watch out for the science papers!

Chang’e 5

Another successful sample grab from offworld was achieved by the Chinese Lunar spacecraft Chang’e 5, which deployed a lander to the Moon’s surface, grabbed about 1.7 kg of moon material, sent a return vehicle (ascender) back to the main spacecraft, and on 16/12/20 got the sample safely back to Earth with a landing in Inner Mongolia.


Recovery team by the Chang’e 5 return vehicle. (Credit: Shutterstock)


Chang’e 5 planting a Chinese flag on the moon. (Credit: CNSA/CLEP). P.S. Awesome logo!

This makes China the third country to return material from the Moon after the USA (Apollo) and Russia (Luna 24, 1976). Robotic missions may lack some of the glamour of crewed space missions, but they certainly get the job done!

NASA Space Launch System (SLS)

While SpaceX are forging ahead with flight testing of their starships, NASA are busy developing their own new Space Launch System (SLS), intended to get people back to the Moon in the relatively near future. During December, a newly-built core stage of the rocket was filled with cryogenic liquid, maintained under operational conditions for a time and then successfully drained. This sets up an engine firing test involving all four of the rocket’s RS25 engines which sit at the base of this core. All this is taking place at NASA’s Stennis Space Centre, Bay St. Louis, Mississippi.

The plan is for a proper launch in late 2021 to send NASA’s Orion capsule (uncrewed at this stage) around the Moon and back, in preparation for a full crewed mission in 2024. When in operation, SLS will be capable of delivering about 27 tonnes of payload to Lunar orbit, which for comparison is not far off a 40ft shipping container filled to maximum weight (30.48 tonnes).


NASA’s SLS core stage on the B2 test stand at Stennis Space Centre, previously used to test the engines for Saturn 5
rockets.


SLS core stage with four RS-25 engines, prior to delivery to Stennis for testing.

A Signal from Proxima Centauri?

Back in April – May 2019, the 64-metre Parkes radio observatory in Australia was being used to observe the red dwarf star Proxima Centauri, our nearest stellar neighbour. One of the two known exoplanets around this star probably has a mass similar to Earth’s, and happens to orbit within the “habitable zone” around the star where liquid water could exist on its surface.

Although the main objective of the observations was to study the powerful stellar flares associated with red dwarf stars, the “Breakthrough Listen” project also used the data to look for signals that might indicate intelligent life. And in October 2020, a signal was detected at a frequency of 982 MHz (that’s 0.305 m wavelength) apparently coming from the region around Proxima Centauri (16 arcminute circle on the sky, or about 1⁄2 the diameter of the full Moon).

There’s work going on at the moment to try to establish whether the signal has a human origin, and hopefully some papers will get published on this. If nothing else, it will help to refine the search criteria for signals of interest to SETI (Search for Extraterrestrial Intelligence) projects and prevent false positive detections. On the other hand, if the signal is really from an extraterrestrial intelligence, we might get the chance to watch their re-runs of soap operas instead of ours (as well as being a transformative moment for our species of course).


The Parkes radio observatory, Australia (Credit: Robert Naeye)

A Walk in the Dark – Moira Greenhalgh

We have all at some time looked up after dusk as the stars popped into view in turn, magnitude one first of all, followed by the less bright stars. It is interesting to see this in reverse.

I take my exercise early in the morning so as to avoid the children gathering to await the school buses. Alarm goes off at 6.25 am and I am out of the house by 6.45 with torch in hand and trustee umbrella. It is still pitch dark. However there have been mornings when it wasn’t actually raining, when the sky was clear.

I step from my gate, and up to my right (NNW-ish) is my favourite star, Capella, not particularly spectacular but reliably always present. I say “good morning” to Capella. Was talking to a friend on the phone last evening and she starts her day with a “good morning Jesus”. Each to our own, if it makes us happy. Walking along the front at Arnside, I see to the west two bright-ish stars lying almost horizontal over the hills towards Grange. They are Castor and Pollux, the twins in Gemini. They form a gentle curve made of Capella, Castor, Pollux and Procyon.

My walk bears round to the left, now facing south-ish, and in front are some fainter stars. I study for a while and can then make out a backward question mark. This is the head and front paws of Leo, and yes now I can see the whole of his body. Further round the circular walk (maybe just east of south) is a bright redish star all on its own. How do I identify it? I hunt around and above it are just discernible 3 stars in an arc, the handle of the Plough. I draw an imaginary line round this arc, and continuing the arc through space I get to my bright star. It is Arcturus in the constellation of Boӧtes. From Arcturus I continue an imaginary straight line (or spike) to a just visible Spica, low in the sky. Something in me says this is all wrong as Boӧtes and Leo are “summer” constellations, I should not be seeing them now.

Actually, I am not seeing them now, time has gone on and the sky is getting lighter though I still need my torch. The stars of Leo have faded out of view as has the handle of the Plough.

However, continuing the walk, facing NE I get to the highlight, the beautiful Venus, shining brightly through the now colouring sky. I stand still, and turn a complete circle. Arcturus is still there, and so is Capella, but the rest have all faded. On the home leg, both these stars gradually reduce to pinpricks and by 7.45 have gone.

Sky Notes this month

See our Sky Notes for January 2021 by Ian Bradley

Recent photos by Ian Bradley and Ted Woodburn

Pictures of the Jupiter -Saturn conjunction

Looks like Ted and I were a few hundred metres apart at Helsington!


Dec 12th, 16:23. Helsington. Credit: Ted Woodburn


Dec 12th, 16:38. Jupiter and Saturn at top left. Credit: Ian Bradley


Dec 12th, 16:51. Jupiter and Saturn.
Credit: Ian Bradley


Dec 12th, 16:56. Jupiter and Saturn. Credit: Ted Woodburn


Dec 12th, 16:56. Jupiter and Saturn. Credit: Ted Woodburn


e Cygnus Loop, a supernova remnant in Cygnus. The right-hand obvious part goes by the names The Veil Nebula and the
Witches Broom Nebula. Taken with a Canon EOS750D and a Sigma 150-600mm telephoto lens @ 200mm. Still a work in progress.
Credit: Ian Bradley


The famous Horsehead Nebula, Barnard 33, in Orion imaged in narrowband Hα at near full moon. Nice to see the streaming
caused by radiation pressure from the exciting star out of shot above. Credit: Ian Bradley

2020 Diary

EAS Meetings and Events in 2020

Due to the coronovirus pandemic, our public meetings have been replaced by internet meetings for member’s.

January 2020

February 2020

March 2020

April 2020

  • Meeting Thursday 2nd in Kendal Museum at 7:00pm event CANCELLED

May 2020

June 2020

July 2020

September 2020

  • Member’s Internet Meeting Wednesday 9th at 7:00pm
    • Intro and set up
    • Speaker: Richard Rae EAS speaking on Mars
    • Speaker: Graham Cornford EAS speaking on A tour of an amateur observatory
    • EAS Newsletter for September 2020

October 2020

November 2020

  • Member’s Internet Meeting Thursday 5th at 7:00pm

December 2020

EAS Newsletter for December 2020

A pdf version of this member’s newsletter which includes an additional section on EAS business and developments is issued to all current members.

See also our monthly Sky Notes for objects observable in the sky from Kendal during this month.

Welcome to the December newsletter. Sadly, on many fronts, the Covid crisis continues, so I hope you all managing to keep well and keep occupied. The weather clearly hasn’t cooperated at all this month. I’ve managed to successfully capture the Orion Nebula, M42, rather close to full Moon using narrow band Hα filter as a test sequence and some views of Mars early in the month. I tried several times later on, got on target only to have to rapidly dismantle as it started raining! It’s so frustrating, I sometimes wonder why I bother! I hope some of you have had better luck.

You will have received from Clive, formal notification of our Annual General Meeting in early January. Obviously, this will have to be by Zoom. The technology is sophisticated enough for you to be able to contribute so I have no doubt that this will be successful. The [short!] AGM will be followed by Prof. Lionel Wilson speaking on “Volcanism on Venus – not quite our twin planet”. What I wish to add here, is that we are losing two officers this year; both Clive and Phil are stepping down after several years of service. I want you to remember that this is your society and that it can’t function without input and, yes, some effort from the membership. Please consider if you could step up and contribute to one of these, or any other, roles

On a positive note, in August, we were approached to contribute to a consultation by a group of MP’s, the All Party Parliamentary Group for Dark Skies, asking for input. I responded on behalf of the Society and heard today that they will publish a policy document on December 9th. Of course, such things have little impact on Government policy, but at least it flags up in Parliament that there are concerned MP’s and voters, so we will see if there is any long-term effect. If you are interested in what you can do to reduce light pollution, have a look at The Institution of Lighting Professionals website, in particular.

Clear skies.

Ian Bradley, on behalf of the EAS committee.

Astronomy Links

We’ve circulated this by email before :

  • Gresham College free Astronomy lecture series by Professors Katherine Blundell and Roberto Trotta. See the Gresham College site and have a look for these and other events. Not all of these are on astronomy.

Astronomy News – David Glass

SpaceX

SpaceX are building Starships as a cheap and re-useable way of getting people and equipment into Earth orbit and beyond. Starship SN8 (design surely not inspired by Fireball XL5?) was looking to be close to a “hop” to an altitude of 15km and a soft landing at the beginning of November. They did a static test fire of the three giant Raptor engines beforehand on 12/11/20 – and something melted. The images below show the very brief test fire in progress, and the situation just after shutdown with something molten dripping to the ground…


Top: Starship SN8 static test fire, 12/11/20. Bottom: Just after shutdown, with molten material dripping from the
underside. Credit: BocaChicaGal, NASASpaceflight.com

You can see the whole thing captured this video.

Starship SN8 is currently in position for launch, and a new Raptor engine is in place.


tarship SN8 in position for “hop” possibly on 30/11/20 (credit: LabPadre, from Nerdle Cam)

A successful test firing took place on Tuesday 24/11/20

A scheduled date is visible in the image above of 30/11/20 sometime between 13:00 and 00:00 UK time for the “hop”, so watch out for it!

World news in November also featured the successful launch of SpaceX’s Crew 1 capsule on a Falcon-9 rocket (also powered by Raptor engines), which went very well. The capsule docked successfully with the ISS, and the first stage booster landed successfully on the drone ship in the Atlantic. This marks the transition to


Baby Yoda asserting command authority aboard SpaceX Crew 1 (credit: NASA TV)

full commercial operation for the capsule, which can ferry people and equipment to the International Space Station. On the way to the ISS, a “zero-gee indicator” was deployed within the capsule by the crew…

Apparently, the use of zero-gee indicators goes right back to the first crewed spaceflight, when Yuri Gagarin released a small doll in the Vostok 1 capsule to prove microgravity conditions while in flight. Bearing in mind that humans have been propelled into space for nearly 60 years now (Vostok 1 was launched in 1961), it does seem right to call it a tradition! The whole Crew 1 launch is available on a 4 hour long Youtube to watch if you missed it – it really is amazing.

Chang’e 5


Chang’e 5 on a Long March 5 rocket, at the point of launch on 23/11/20 (credit: China News Agency)

A mission to retrieve around 2kg of Moon rock was launched from China on 23/11/20. The Chang’e 5 mission intends to deploy a robotic lander which will drill down to a depth of about 2m to retrieve pristine material, and scoop material from the surface. The lander also has instruments for analysing the surface. The landing zone is on the near side of the moon, where the surface is predicted to be around 1.2 billion years old (compared to the Apollo samples which go back to around 3 – 4 bllion years). The lander will be deployed from an orbiter, and an ascent vehicle with the lander will carry the rock back to the orbiter which will then head back to Earth. The rocks will be transferred to a sample return capsule for return to Earth’s surface in mid-December. All this is being done robotically, which will be an impressive feat.

For a neat animation of how the sampling and return to Earth is intended to happen, see here.

 

Tragedy at Arecibo

The Arecibo radio telescope in Puerto Rico has been at the forefront of radio astronomy and atmospheric studies since 1963, and as well as contributing to the SETI programme it has featured in notable film and TV appearances such as Goldeneye (1995) and a very creepy episode intro for the X files: see here.

The 305m dish, needed to achieve the required angular resolution and sensitivity at the radio frequencies of interest, has suffered damage in the past but had been repaired. However, the breakage of two cables holding up the receivers within a short space of time left the dish beyond economic repair. Two such failures in close succession could mean that all the cables are weaker than they should be. The decision has now


The Arecibo radio telescope, with a 305m dish and receivers mounted on cables.
Credit: Mariordo (Mario Roberto Durán Ortiz


The damage suffered after the second cable failure on 6/11/20 (source: CNN)

been made to decommission the telescope.

Fortunately, radio astronomers are not left without observing tools of this power. The FAST telescope in China, based on similar design principles to Arecibo, became fully operational this year and has a 500m dish. There is also the multiple-dish Very Large Array (VLA) in New Mexico, USA, which uses interferometry to achieve high angular resolution. Other smaller telescopes are also available including the Lovell Observatory in Cheshire, which can work together to form a giant interferometric telescope.

Phosphine in the Atmosphere of Venus

On 14/9/20, a team of astronomers led by Prof. Jane Greaves of Cardiff University announced the detection of phosphine (PH3), an organic molecule associated with biological processes, in the atmosphere of Venus ( see here for a version of the paper). They used observations from the ALMA interferometric telescope in Chile and the James Clerk Maxwell Telescope (JCMT) in Hawaii for this. A dip in brightness in the spectrum of Venus at a wavelength near 1mm was seen with both telescopes

This is exciting, as it could indicate microbial activity in Venus’ atmosphere. Another study, looking at data from the Pioneer satellite, also indicates that phosphine could be present: see here.

However, nobody expected the response from groups within the astronomy community. During October, three papers were released on ArXiv claiming that the detection is false:

One paper stated that the spectral line detected is from sulphur dioxide (SO2), while the others could not extract the phosphine spectral line in the data. Another paper put an upper limit on the concentration of phosphine that is below what was measured, see here.

The original team did not take this lying down. In a subsequent paper, the team re-analysed the data taking into account the methods and findings in the October papers – and still found evidence of phosphine (although it was at lower concentrations than previously thought): see here.

The papers also stress that better observations are needed to really confirm the result. It would also be great to send a spacecraft to actually sample the atmosphere.

All of the above shows a useful process at work, where findings in papers are challenged (hopefully in a constructive way!) and results are updated to reflect new knowledge and approaches. Studies like these are out to get at the truth, and sometimes that can be frustrating!

The Blue Ringed Nebula – Ian Bradley

I typed the title and it immediately brought to mind a humorous Australian song – I’ll say no more other than suggest you Google ‘blue-ringed octopus song’. To paraphrase another comedy act, and now for something completely different and serious.

Just over a week ago, an article in the journal Nature caught my eye; a discussion on observations of the Blue Ringed Nebula – with the exciting star having the formal name of TYC 2597-735-1. This rather delicate and pretty object, which is what caught my eye, resembles a planetary nebula but is actually the result of a recent (a few thousand years ago) stellar merger.

The [complicated] 15’ x 15’ false-colour image is a mixture of far-UV, near UV and Hα images from the GALEX spacecraft. The image shows two clear rings radiating at the Hα wavelength (red) – in other words excited hydrogen atoms plus a far-UV emission (blue) and a shock front visible in near-UV. The small insets labelled b, c & d show the object in the three wavelengths bands studied. The Hα emission, radial-velocity variations, enhanced ultraviolet radiation and excess infrared emission suggest the existence of a dusty circumstellar disk. The blue ring comes from fluorescing hydrogen H2 and only appears where the ejected two cones overlap in our line of sight as can be seen at bottom right. The speed of the outflow is 400km s 1 – 0.1% of the speed of light!

What their modelling suggested is that matter flowed from the larger star onto the companion resulting in the companion star spiralling inwards, and eventually merging. Most of the ejected matter ended up gravitationally bound and formed a circumstellar disk which eventually cooled and formed dust. The merger ejects more material but this is shaped by the circumstellar disk leading to the two cone structures. This ejected material sweeps up interstellar material and the resulting shock front causes the Hα emission.

This object provides a unique opportunity to study post-merger behaviour. See the original paper and for a clearer picture of what is going on.

Neutrinos from the CNO fusion cycle in the Sun detected – Ian Bradley

Our Sun is a natural fusion reactor, and fusion releases neutrinos. There are millions per second of solar neutrinos passing through your fingernail but they don’t interact. In the late 60’s Ray Davis used a tank of perchloroethylene, dry cleaning fluid, deep underground to detect neutrinos – and there were too few compared to what was expected – the solar neutrino problem. That mystery was solved in the 90’s. So now what is new?

In a star like our Sun, it was expected that the dominant fusion process is what is called the p-p chain, where a pair of protons fuse to create deuterium, which then fuses with a third proton to create helium-3. Finally, two helium-3 nuclei fuse to create a helium-4. This process, and two other slight variations, produce 99% of fusion energy in the Sun. However, it was believed that a rare alternate process, called the CNO cycle, should produce the remaining 1%, but there was no evidence for this process. It is important to understand this process too because in higher mass stars, stars over 1.3 times the mass of the Sun, it was expected to be the dominant process.

Schematic of the Borexino Experiment

The scale is impressive

Just a few of the 1800 photomultiplier tube detectors to detect the faint flash as neutrinos interact.

The CNO cycle is a fusion of protons with carbon, nitrogen and oxygen nuclei in a six-step process that creates one helium-4 nucleus before repeating itself. It produces a different and distinct neutrino spectrum compared to that from the pp chain. And that it what the Borexino collaboration has now measured.

This experiment has a 280 tonne scintillator target, and detects solar neutrinos when they collide with electrons in the scintillator. As the electron recoils it produces light, which is captured by an array of photomultiplier tubes. Despite the enormous neutrino flux, only tens of neutrino are detected daily. The experiment is deep below the Gran Sasso mountain in Italy to shield it from the vastly larger cosmic ray signal. After a difficult and technical analysis, the Borexino team have now confirmed the tiny signal and is consistent with the expected 1% of the Sun’s energy production by this route. It also opens a door to answer the questions about the ‘metallicity’ (elements other than hydrogen and helium) of the Sun – but needs more data and probably a new improved detector.

See here.

Constellation of the month – Moira Greenhalgh

This month I have chosen Perseus. It is circumpolar and can be seen most of the year, but it is particularly good now. So, what does it look like, and how do you find it?

The W of Cassiopeia is clearly visible in the NE just after dark, moving to E by about 8.00 pm. The constellation of Perseus is just below.

Perseus was the Greek hero who slew the gorgon Medusa. She had snakes for hair and anyone looking at her turned to stone. [Digression – jellyfish are called Medusa after her]. Perseus got around this by not looking directly but using his shield as a mirror. He is always shown in pictures carrying her head and usually holding a mirror. The star Algol is her evil eye. He then rescued Andromeda from the sea monster, Cetus, a story

Ancient Corinthian vase depicting Perseus, Andromeda and Ketos (Cetus), photo: BishkekRocks

with a long history, as shown on the vase.

Most of the Perseus family of constellations are part of this myth, Cassiopeia and Cepheus were Andromeda’s parents, and Pegasus, the winged horse, was supposed to have sprung from the body of Medusa.

Back to the constellation. It was one of the 48 ancient constellations listed by Ptolemy in the 2nd century, and is 24th in size of the 88 modern constellations.

The brightest star is Mirfak (α Persei), a yellow-white supergiant, magnitude 1.79, located around 590 light years from Earth. It and many surrounding stars are members of an open cluster, the Alpha Persei Cluster.

The most well-known star is Algol (β Persei), Medusa’s evil eye. Algol means “the Demons’ head” in Arabic. In Hebrew tradition it is known as “Satan’s Head”. Very ominous. Around 92.9 light-years from Earth, its magnitude appears to vary from 3.5 to 2.3 over a period of days, and this is visible to the naked eye. It was thought to be an eclipsing binary system but a third star makes it a triple star system. The two main stars are very close together, 0.05 AU, and the main dip in brightness is when the larger, fainter passes in front of the hotter, brighter primary star. It gives its name to a group of eclipsing binary stars known as Algol variables. Around 7.3 million years ago Algol passed within 9.8 light years of the solar system, when its apparent magnitude would have been around -2.5, very much brighter than Sirius is today.

At least 7 stars in Perseus are known to have exoplanets

The Perseus Arm is a spiral arm of the Milky Way, towards the rim of the galaxy, which stretches across the sky from Cassiopeia through Perseus and Auriga to Gemini and Monoceros. Within this arm are two open clusters known as the Double Cluster, NGCs 869 and 884. They lie in the sky between Cassiopeia and Perseus and are easy to find.

Clearly visible in binoculars, they make a wonderful sight through an amateur scope, with both clusters in view.


Finding the Double Cluster


The Double Cluster in Perseus. Photo: Fred Espenak

 

Other Deep sky objects include open cluster M34, which is best viewed through a telescope. The Little Dumbbell Nebula, M76, is a planetary nebula and emission nebula NGC 1499, which is known as the California Nebula. There are also a host of galaxies.

Little Dumbbell Nebula (M76)

Little Dumbbell Nebula (M76) Image: Adam Block, Mount Lemmon SkyCenter, University of Arizona

California Nebula, NGC 1499, an emission nebula close to the star Menkib
Credit: Rosa remote.com, photographer Martin Rusterhotz

The Perseids are an annual meteor shower in mid-August which were always a highlight of my childhood holidays in W Wales. They are associated with comet Swift-Tuttle.

Cepheid variables and distance – Ian Bradley

At our November Zoom meeting, there was a brief discussion following Richard Rae’s talk about how Cepheid variable stars were used to determine the distance to the Andromeda Galaxy, M31. Given some confusion, I thought it might be worthwhile to write something on the topic…

Cepheid’s are one of over a dozen different types of variable star types and are particularly useful as a so-called ‘standard candle’. They are a particular class of [short period] regularly pulsating stars where the varying light output is determined by something internal to the star.

Leavitt’s plot from the 1912 paper. The horizontal axis is the logarithm of the period (in days) and the vertical axis vertical axis is the apparent magnitude (brightness). The lines drawn connect points corresponding to the stars’ minimum and maximum brightness, respectively

Henrietta Swann Leavitt was looking at Cepheid variable stars in the Small Magellanic Cloud, a tiny close galaxy that orbits our galaxy, and noticed that there was a relationship between each star’s pulsation period and its brightness (apparent magnitude). She then assumed that all these stars were roughly the same distance away, with meant that this same simple relationship between the pulsation period and the luminosity (or absolute magnitude) of the star must also be true.

This is a stunning result as it implied from a measurement of the period you knew the absolute magnitude, so that a measurement of the apparent magnitude allows you to calculate the distance using the Inverse Square Law.

The problem was, no one knew the distance to the Small Magellanic Cloud so Leavitt couldn’t convert her apparent magnitudes to absolute magnitudes.

 

Apparent and Absolute Magnitudes

In ancient times, someone classified stars by their brightness to the eye. The brightest visible stars were given magnitude 1 and the faintest magnitude 6. Our eyes are logarithmic in sensitivity, so this ancient scale also is logarithmic, with each magnitude corresponding to about 2.5 times less light. This means there is 100 times less light from a mag 6 star as from a mag 1 star.

This brightness as seen from Earth is the apparent magnitude. To allow intercomparison between different stars at different distances, it is useful to compare their properties as though they were all at the same distance (10 parsec, ~3.3 light years). If the distance to the star is known, it is easy using the Inverse Square Law, to calculate how bright the star would be if it was at 10pc. This is known as the absolute magnitude.

 

The Inverse Square Law

The inverse square law is simply a geometric effect and describes the dimming as distance increases away from the light source. If the distance increases by some factor, the brightness dims by 1/factor2, hence the name inverse square law. For example, on doubling the distance of a star, the brightness drops by a factor of 4 but its magnitude increases by 1.5. Double distance again, and the magnitude increases by another 1.5

The solution was to find a Cepheid variable that is relatively nearby where measurement of the distance using parallax was possible. Once that was done, the apparent magnitude of that star and its distance allowed the calculation of its absolute magnitude. As this period and absolute magnitude of one Cepheid was now known, every other Cepheid period could be converted to an absolute magnitude and using the observed apparent magnitude, the distance could be calculated.

The Parallax Method

As the Earth goes round its orbit, nearby stars apparently move against the background of very distant stars. Measuring these tiny angular changes (for the nearest star Proxima Centauri, this is less than 1 second of arc) and using simple geometry, the distant can be calculated. This relies on knowing the distance from the Earth to the Sun (and that’s another story – the 1st step in the Cosmic Distance Ladder).

The great thing is that if you can now find Cepheids and measure their periods in other galaxies, we can deduce the distance of these stars and therefore that of their galaxies. It was this process that allowed the first reliable estimate of the distance to M31.

Winter Coloured Double Stars – Ian Bradley

Double stars can be very pretty, especially if the two stars have contrasting colours. Double stars have the advantage that they are little affected by light pollution or the phase of the Moon, unlike for example the faint fuzzy blobs of galaxies.

Splitting very close doubles can be an interesting challenge but you may be limited by the resolution of your optics. A very rough rule of thumb is that on an ideal night [do we get those in Cumbria?] your binoculars/telescope can resolve objects that have an angular separation of 140/aperture in mm [5.5/aperture in inches], so for a pair of 10×50 binoculars, you could separate stars if they are 140/50 ~ 3 arc seconds. I suspect 5 arc seconds might be a more likely possibility in this case.

Generally double stars with a colour difference are more interesting and beautiful to observe, especially if they are not too different in brightness. Having said that Castor, α Geminorum, is a pretty double with both stars being white and having a similar brightness.

One classic and the rather lovely double star is Albireo in β Cygni – the head of the swan.

 

The picture above is one I took in September using my 8” Meade SCT and a Canon DSLR. The primary star is a lovely golden yellow at magnitude 3.4 whilst the companion at magnitude 4.7 is a lovely blue colour. They are just splitable using a x20 magnification.

The annotated right-hand picture defines a few of the numbers in the table below. North is up as seen in binoculars, but be careful here as different styles of telescope with give different orientations (never mind the effect of a star diagonal!). For example, a Newtonian, Dobsonian or refractor will give west to the left and north down, whilst a Schmitt-Cassegrain or a Maksutov will give North up and East to the right [as will a refractor and a diagonal).

So what do the labels mean? The separation is just the angular separation in arc seconds of the two stars, whilst the position angle is the angle of the line joining the two stars measured going in a direction through east – so can vary from 0° to 350°.

In the table below;

  • are the positional coordinates RA (Right Ascension) and DEC (declination), the equivalent of latitude and longitude;
  • the magnitudes of the two stars;
  • the colour difference where the bigger the number, the more distinct the difference, determined from the spectral class [colour] of the stars;
  • Finally, the optimum magnification based on the opinion of Alan Adler. He found that doubles look their best at a magnification that is approximately 750 divided by the separation in arcseconds. So, for Alberio, where the separation is 35”, 750/35= 21, so 21x magnification looks best. This is a rather subjective measure and don’t worry if you can’t get this ‘optimum’. For example, with my Meade, my minimum magnification is 77x and Alberio looks great!

Sometimes, the human brain plays tricks on you. Despite the temperature of a star, which fixes the colour and the spectral class, if the brighter star has a strong colour, you perceive the fainter star to have the complementary colour [for red that is cyan] rather than its true colour! You’ve probably seen this with an afterimage after looking at a bright coloured object. This is a nice website on this point. And different people see slightly different colours just to confuse things even more.

The following is a list of winter coloured double star systems worth looking at for their colours, based on a 2016 article in Sky and Telescope by Bob King1 – who based his article on an earlier one by Alan Adler2. You might need some planetarium software to find some of these pairs.

Star R.A.         Dec.      Mags. Sep. P.A. Colour difference Spec. Class Optimum magnification
η Cas 00h 49m +57° 49′ 3.5 7.2 13″ 317° 1.7 G0, K7 58x
1 Ari 01h 50m +22° 16′ 5.9 7.2 2.9″ 164° 3.5 K1, A6 268x
γ And 02h 04m +42° 20′ 2.1 4.8 9.8″ 64° 3.5 K3, B8 77x
ι Tri = 6 Tri 02h 12m +30° 18′ 5.3 6.7 4″ 69° 1 G5, F5 188x
η Per 02h 51m +55° 54′ 3.8 8.5 28″ 301° 3 K3, A3 27x
32 Eri 03h 54m –02° 57′ 4.8 5.9 7″ 254° 2.6 G8, A2 107x
ρ Ori 05h 13m +02° 52′ 4.6 8.5 7″ 64° 1.7 K3, F7 107x
14 Aur 05h 15m +32° 41′ 5.0 7.4 15″ 226° 0.4 A9, F3 50x
ι Ori 05h 35m +05° 57′ 2.9 7.0 10.9″ 142° 0.2 O9, B1 69x
ι Cnc 08h 47m +28° 46′ 4.0 6.6 30.6″ 307° 2.6 G8, A2 25x
ζ Lyr 18h 45m +37° 36′ 4.3 5.6 44″ 150° 1.1 B7, A8 17x
Albireo 19h 31m +27° 57′ 3.4 4.7 35″ 54° 3.5 K3, B8 21x
31 Cyg 20h 14m +46° 44′ 3.8 4.8 107″ 325° 2.9 K2, B3 7x
β Cap 20h 21m –14° 47′ 3.2 6.1 207″ 267° 3.2 K0, B8 4x
γ Del 20h 47m +16° 07′ 4.4 5.0 9″ 267° 1.4 K1, F7 83x
δ Cep 22h 29m +58° 25′  4.1 6.3 40.9″ 191° 2.5 G2, B7 18x

Some recommended highlights:

  • Eta (η) Cas:  Exquisite at 64× with a pale-yellow primary and purple-red secondary.
  • Alberio β Cas: Lovely yellow primary and blue secondary but some people see yellow and white!
  • 1 Ari: A close pair. Orange and blue – a good example of complementary colour.
  • 14 Aur: Yellow and pale orange; subtle.
  • η Per: Reddish-orange and blue-green. Another example of complementary colour.
  • 32 Eri: Yellow-orange and blue. A close pair, so use 100× or higher to see the colours more clearly. Could be a challenge to find.
  • Iota (ι) Ori: Two pure white suns. No colour difference, so no false contrast here!
  • Gamma (γ) Lep: Striking gold and green! Of course, since there are no green stars, the complementary perception effect is at play here. Sadly, this is quite low, below Orion, but worth a try

I’ve only seen a few of these but I hope to see some more. I hope you can see some too.

Recent Photos

Mars, November 3rd 2020. The dark triangular feature is the Syrtis Major. The south polar ice cap is also visible. 8” Meade LX200R, x5 Barlow, Can 750D DSLR. Credit: Ian Bradley

The Orion Nebula M42 imaged in Hα, the light from hydrogen using an EOS clip filter. Given it was nearly full Moon, a standard colour image would have been washed out. This is only 10 minutes exposure in total so it has plenty of potential to capture subtle . Credit: Ian Bradley

EAS Newsletter for November 2020

Welcome to the November newsletter.

A pdf version of this member’s newsletter which includes an additional section on EAS business and developments is issued to all current members.

See also our monthly Sky Notes for objects observable in the sky from Kendal during this month.

Well this situation just keeps going on… There doesn’t look like there is much of a chance of having real physical meetings until some indeterminate time in the new year. So, we’ll have to make do with Zoom. As many of you will know, last month we had an excellent talk by Sue Bowler on Finding Black Holes. The committee was pleased that so many attended. It does give a good impression to the speaker and makes them feel their effort was worthwhile. So, thanks to you all.

This month, David Glass and Richard Rae will speak on “Galaxies – an evolving story“. This will be in two parts. First, Richard Rae will do a piece on the “Great Debate” which established galaxies as being very distant and outside of the Milky Way. David will then cover the first attempt at classifying galaxy morphology (Hubble’s tuning fork diagram) and how the relationship between morphology (shape) and galaxy evolution has turned out to be a lot more complex. Look out for the email with the meeting joining instructions. Hopefully you’ll all make it.

Over the next few months, we have Graham Fell’s often hilarious and generally quite challenging annual astronomy quiz in December, and Professor Lionel Wilson in January. Lionel’s talk ‘Volcanism on Venus – not quite our twin planet’ had to be postponed in June. Further ahead, in March, Dr Megan Argo will speak to us about the “The future of radio astronomy – the Square Kilometre Array” deferred from last April. David Glass is working on the programme for 2021 so if you’ve any suggestions, he would be glad to hear from you.

The clouds haven’t played that fair this month so my views of Mars at opposition have been somewhat limited. I hope you all did better.

Clear skies.

Ian Bradley, on behalf of the EAS committee.

Astronomy News – David Glass

Salyut 7

This year sees the 35th anniversary of a daring mission to salvage a derelict space station, which has all the hallmarks of a good sci-fi film. In fact, it’s been dramatized in a film made in 2017!

The Soviet space program launched 7 Salyut space stations in all, the first (Salyut 1) in 1971 and the last (Salyut 7) in 1982. It’s a shame that their history and achievements of these stations aren’t talked about much! (perhaps someone would like to put together a talk for us on this – yes that is a hint!!).

Salyut 7 was uncrewed in the early part of 1985. On 12th February, circuit breakers tripped and left the station without power, tumbling and with internal temperature dropping. Because the Mir space station was delayed, a mission was planned to board Salyut 7 and restore it to working order. So, on 6th June 1985 two cosmonauts (Vladimir Dzhanibekov and Viktor Savinykh) were launched to get on board – which they did. The station was equipped with an automatic docking system, but this was down and the cosmonauts had to dock manually by matching the rotation rate of the station (name a sci-fi movie where that was done!). Luckily this was manageable, and Dzhanibekov had experience of this procedure. Once inside they found that they could repair the station – and spent the next ten days doing so in freezing conditions.

Salyut 7 Source: Wiki

Salyut 7 Source: Wiki

Viktor Savinykh soon after boarding Salyut 7

Viktor Savinykh soon after boarding Salyut 7, hence the woolly hat (Crew of Soyuz T-13). Source: https://astronomy.com

They opened up portholes to let sunlight in, and connected the last operable batteries to the solar panels to energise key systems. They could then use the station’s thrusters to stabilise it and align it properly with the Sun. After that, they could begin restoring lights, communications, and air and water supplies. Conditions were harsh for the cosmonauts, but they did it!

Their journey didn’t end there – with the station in operation again, Dzhanibekov stayed for 110 days, while Savinykh spent a further 168 days on the station (coming back on a different spacecraft).

I’ve just found that the film Salyut 17 is on Amazon Prime Video (N.B. no endorsement implied!) – I’ll let you know what it’s like!

Who could be listening in?

Astronomers have managed to detect exoplanets by watching them transit their host star, sometimes from back yards. The very slight dip in brightness of the star as a planet passes in front of it can sometimes be measured. One team of researchers chose to reverse the question – from what nearby stars could Earth be detected in the same way? This involved choosing stars whose alignment with the Sun meant that Earth would be seen as passing in front of it. The result – 1004 stars within 100 parsecs would be good vantage points, and the view from 508 stars would achieve a transit time of at least 8 hours.

Thanks to data from the Gaia satellite, the properties of these stars are known and the researchers have produced a catalogue which includes the likely orbital properties of exoplanets within the “temperate zone”, where liquid surface water could exist. This will be of use in designing observation programmes to find exoplanets where some other intelligent species could be designing exactly the same study!

Hertzsprung-Russell diagram of the stars within the Earth Transit Zone (ETZ). For comparison, our Sun has an effective temperature (Teff) of 5,800K. Cooler stars are dwarfs like our Sun, while hotter stars are giants (Kaltenegger & Pepper 2020).

See this paper.

Betelgeuse yet again

Always a star for surprises (see previous newsletters!), Betelgeuse has thrown another curve-ball. This time, researchers have found two dimming events in 2019 – one due to a dust cloud as discussed in previous newsletters, the other (smaller) due to stellar pulsations. Analysis and computer modelling of the pulsations suggests that Betelgeuse is burning helium at its core, and is therefore quite some way off going supernova (maybe 100,000 years off, i.e. not imminent). Also, the results suggest that Betelgeuse is actually smaller than thought (only 2/3 of the distance from the Sun to Jupiter, not all the way out) and is 25% closer to the Sun (548 light years). This is still a good safety distance for a potential supernova! Which of all the recent papers on Betelgeuse and its fate turns out to be correct will only become apparent over time.

See this research paper.

Imaging a giant nearby exoplanet

The list of exoplanets which have been observed directly has increased by one. Beta Pictoris c, an exoplanet about 9 times the mass of Jupiter, has been imaged using four optical telescopes that form the VLT and the GRAVITY instrument. Beta Pictoris b, an exoplanet 11 times the mass of Jupiter, has been imaged previously. Discovery of Beta Pictoris c by the radial velocity method was first announced in 2019.

The newly imaged exoplanet is closer to the star than its companion (2.7 AU compared to 9.8) and completes an orbit every 1,200 days. The system is still relatively young, with a dusty disc still part of it, and the exoplanets within it are thought to be around 10 million years old. The observations also constrain the exoplanet’s properties such as brightness and mass, which are of use to astronomers modelling exoplanet formation processes.

The papers on this can be found here and here

An image of Beta Pictoris b and c within the dusty disk

An image of Beta Pictoris b and c within the dusty disk surrounding Beta Pictoris. (Axel Quetz / MPIA Graphics Department)

OSIRIS-REx and Bennu

NASA’s OSIRIS-Rex mission to retrieve a sample of nearby asteroid Bennu has received a lot of media coverage recently, after its successful contact with the asteroid surface and sample acquisition. See here.

Therefore, we won’t dwell on it here.

However, one alarming piece of news turned up on the BBC website, stating that a small piece of rock had jammed open the sample chamber door and the sample was leaking out. I sincerely hope that some sample gets back at least!

See here.

SpaceX

No spectacular hops or major releases of cryogenic liquids of late at SpaceX’s Boca Chica site in Texas… but, something interesting is happening at the time of writing. The image below from LabPadre’s NerdleCam on Youtube shows Starship SN8 stacked with its nosecone on. It certainly looks the part! Also visible are cryogenic vapour being vented near a number of very large horizontal vacuum-insulated storage tanks, and what looks like a road tanker for delivering cryogenic liquids in front of the vessels. Venting like this can happen when cooling down vessels and pipework to operating temperature using a slow feed of cold liquid, or by displacement of vapour during filling of vessels. Three hydraulic platforms are in place by SN8, and people appear to be working up there.

It therefore may not be long before SN8 does a “hop”, possibly to a significant altitude, so keep checking the live feeds!

Water on the Moon – Ian Bradley

You will probably have heard about NASA finding water on the Moon. This isn’t a first but a very important discovery. In August 2018, NASA reported finding water ice in the lunar polar regions using NASA’s Moon Mineralogy Mapper (M3) instrument aboard the Indian Chandrayaan-1 spacecraft. At the south pole, this is primarily in craters where the Sun never shines. At the north pole, this is much more sparsely spread.

The distribution of surface ice at the Moon's south pole (left) and north pole (right). Blue represents the ice locations, plotted over an image of the lunar surface. The darker gray corresponds to colder areas and the lighter grey warmer areas.

The distribution of surface ice at the Moon’s south pole (left) and north pole (right). Blue represents the ice locations, plotted over an image of the lunar surface. The darker gray corresponds to colder areas and the lighter grey warmer areas. Credit: NASA

So what is all the fuss about now? From infra-red spectroscopy measurements from 2009, it was known that there were characteristic absorption features at 3μm possibly from water. However, at this wavelength, there is no way to distinguish molecular water (H2O) from other OH compounds, so it wasn’t clear if there was water outside of the polar region craters.

The new measurements reported in Nature Astronomy, sadly behind a paywall , are measurements at 6μm which unambiguously can identity molecular water. Using the airborne NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA), they observed high southern latitudes near the crater Clavius and a low-latitude portion of Mare Serenitatis. They looked for a difference between the two regions. It is clear that there are distinct absorption features in the Clavius region that indicate there is H2O at the level of 100-400μg/g material. It is expected that the water is trapped in the interior of impact glasses although there have been suggestions it might be in the gaps between grains. The authors also believe this water is a local geology effect and not a global phenomenon.

It needs to be stated that this isn’t a huge quantity of water – no glaciers, streams etc but the observation that there is water outside of the polar craters gives some hope that future astronauts may be able to extract water from the surrounding regolith elsewhere. Paul Hertz, NASA’s Director of Astrophysics, stated

“We had indications that H2O, the familiar water we know, might be present on the sunlit side of the Moon. Now we know it is there. This discovery challenges our understanding of the lunar surface and raises intriguing questions about resources relevant for deep space exploration.”

Rosetta, Philae and Comet 67P/Churyumov-Gerasimenko – Ian Bradley

Remember the fantastic Rosetta Mission to Comet 67P/Churyumov-Gerasimenko? Its lander Philae descended to the surface of the on 12 November 2014 and bounced after its anchoring harpoons failed. After another two-hour flight, Philae bounced again off a cliff, and rolled into a crevice. It was finally found in the Rosetta imagery nearly 2 years later. But where was this bounce?

It was announced today, October 28th, that after a remarkable detective story, ESA’s Laurence O’Rourke has solved this. The team knew from the data that Philae had dug into the surface and probably exposed clean but primitive (billions-of-years-old) ice. Reanalysing the touchdown data, he found that Philae spent nearly two minutes at the bounce site, creating at least four distinct surface contacts as it ploughed across it.

To cut a long story short, the impact left a bright area of clean ice of about 3.5 square metres and some 30m away from Philae’s final resting place. This scar was really prominent in later imagery of the area being brighter because the impact removed the dark surface caused by space weathering and micro-impacts – you probably remember that the comet nucleus was really dark. Data from its magnetometer boom allowed the team to figure out which direction it was pointing and the timing as it spun, slid and rolled during these few minutes of this second contact. One particularly imprint revealed in the images was created as Philae’s top surface sank 25 cm into the ice on the side of a crevice, leaving identifiable marks of its drill tower and sides.

The lander rolled over a boulder that looks a little bit like a skull wearing a hat. O’Rourke said “The right ‘eye’ of the ‘skull face’ was made by Philae’s top surface compressing the dust while the gap between the boulders is ‘skull-top crevice’, where Philae acted like a windmill to pass between them.”

The bounce point (APOD 12 Sept 2016) and Philae’s final position with the obvious impact scar. The right-hand pictures show Skull Rock and the dent made by Philae.

The bounce point (APOD 12 Sept 2016) and Philae’s final position with the obvious impact scar. The right-hand pictures show Skull Rock and the dent made by Philae. Credit: ESA

The impact that created the ‘eye’ also allowed the researchers to determine that the boulder had the constituency of ‘cappuccino froth’ and really porous, consistent with earlier measurements on the nucleus as a whole. These measurements really indicate the mechanical strength and structure of the comet when it formed 4.5 billion years ago.

There are some nice animations here

There is a commentary on the final Nature paper here and also here. The full paper is behind a paywall.

Constellation of the month – Ian Bradley

Sorry, Moira is unavailable so you’ll have to put up with me!

Since Pegasus is due south around 21:00 mid-month, it seems a logical choice. It is also frequently overlooked due to its neighbour Andromeda, especially so given that that contains the M31 galaxy.

Credit: IAU and Sky & Telescope magazine

The usual fanciful depiction of Pegasus and Equuleus, the foal. This comes from Urania's Mirror, a series of constellation cards from the early 1800’s. Credit: National Museums of Scotland collection.

The usual fanciful depiction of Pegasus and Equuleus, the foal. This comes from Urania’s Mirror, a series of constellation cards from the early 1800’s. Credit: National Museums of Scotland collection.

Pegasus is one of Ptolemy’s original 48 constellations and named after the mythological magical winged horse. Pegasus is one of the offspring of the gorgon Medusa (the other being Chrysaor who I’ve never heard of) and the god Poseidon, both ‘born’ when Perseus chopped off Medusa’s head. Perseus then flew away on Pegasus. During this flight, he spotted Andromeda chained to a rock… and rescued her. The rest they say is ‘history’. Now Pegasus, Andromeda and Perseus line up next to one another…

The most obvious thing about this constellation is the four magnitude 2 stars forming the asterism of the Square of Pegasus. Ironically, the brightest star, Alpheratz, belongs to the constellation of Andromeda! Markab α-Pegasi, Scheat β-Pegasi, and Algenib γ-Pegasi, together with Alpheratz α-Andromedae (also designated δ−Pegasi) form the square and the orange super giant Enif ε-Pegasi marks the muzzle. Enif, which means The Nose in is actually the brightest star in the constellation. Scheat is an irregular variable star similar in behaviour to Betelgeuse. It varies in magnitude from 2.3 to 2.7. Although the diameter changes as the star‘s brightness changes, it is estimated to be about 150 times larger in diameter than our Sun. In other words, it would nearly fill the space inside the Earth’s orbit around the Sun! As its mass is estimated to be only 9 times that of the Sun, it is literally a ball of hot gas. It would make a nice eyeball or binocular measurement project using Markab and Algenib as comparison stars. The AAVSO gives a period of 43.3 days…

Algenib is also variable although the changes are very small (0.04 magnitudes) and very rapidly changing (3.64h). It is a β-Canoris Majoris is type variable, a class of variable stars that exhibit small rapid variations in the variability of Scheat.

The Globular Cluster M15.

The Globular Cluster M15. Credit: Ian Bradley

The most obvious deep sky object is the globular cluster M15. AT magnitude 6.4 and 12’ in diameter (~1/3rd that of the Moon) it is relatively easy to find. Just follow the line joining θ to Enif and continue beyond Enif another 4° (about half the field of view of a typical pair of binoculars). My book describes it as ‘a very nice example of a globular cluster that dominates the autumn skies. It has an intense starlike centre…’ (K. Graun: Finding and Viewing the Messier Objects). Most other objects deep sky objects require a telescope. A few degrees north west of Matar, η-Pegasi, lies the Deer Lick Group of galaxies. Dominated by the spiral NGC 7331, y 40 million light years distant, a is group of about 6 galaxies. Just 30’ away lies Stefan’s Quintet, a group of 4 fainter gravitationally tidally disrupted galaxies with another one in the same line of sight. Have a look at the fabulous image on APOD

The Deer-Lick group with Stefan’s Quintet to the lower right.

The Deer-Lick group with Stefan’s Quintet to the lower right. Credit: Tom Matheson http://www.guidescope.net/galaxies/stephan- deer.htm

Imaging this could be quite a challenge.

 

Recent Photographs

 Venus rising over Kendal. 15th October 05:57 hrs. 24mm, 4 sec, f 2.8 iso 1600. Credit: Ted Woodburn

Venus rising over Kendal. 15th October 05:57 hrs. 24mm, 4 sec, f 2.8 iso 1600. Credit: Ted Woodburn

Mars and the mushroom, Scout Scar. 15th October, 05:50hrs, 24mm, 5sec, f2.8, iso 1600

Mars and the mushroom, Scout Scar. 15th October, 05:50hrs, 24mm, 5sec, f2.8, iso 1600. Credit: Ted Woodburn

Mars high above Kendal Castle, from Queens Road. 12th October, 22:13hrs, 24mm, 1.6sec, f2.8, iso 1600

Mars high above Kendal Castle, from Queens Road. 12th October, 22:13hrs, 24mm, 1.6sec, f2.8, iso 1600 Credit: Ted Woodburn

The Moon and Venus from Kendal, 14th October 07:03 hrs, 200mm, 1/100 sec, f4, iso 1600

The Moon and Venus from Kendal, 14th October 07:03 hrs, 200mm, 1/100 sec, f4, iso 1600. Credit Ted Woodburn

 

A work in progress. The image on the left is the whole of the Cygnus Loop, a supernova remnant. This was taken with my Canon 750D which isn’t very sensitive to the red of hydrogen emission. It is a huge, roughly ‘spherical’ structure. The + marks where the original star is believed to have been./p>

The Moon for scale. [The Moon can never be where I’ve put it!]

The nebula complex is something like 6 times the diameter of the Moon. A 1hr exposure [40 x 1.5 minutes exposures at iso 1600, f#5].

The left-hand picture below is NGC6992 & 6995 in good conditions and included in last month’s newsletter. The right hand one is my second attempt at NGC6960, The Witches Broom Nebula. Sadly, I think I had moisture on the optics, hence the halo. My picture of Pickering’s Triangle is even worse! I didn’t spot the moisture until several days later when I looked down the telescope tube in the house… Through an eyepiece, all looked fine…

I guess that it is until next year as I might struggle to get the 6 hours of exposure necessary for the 3 frame mosaic. This astrophotography game can be frustrating! Credit: Ian Bradley

Mars, October 15th ,02:05 BST. Not great but about the best I can do at the moment. North is up.

Meade LX200R, x5 Powermate, Canon 750D, movie mode. Best 10% of 5189 frames @ 25 frames per sec. Processed with PIPP, AS3 and Registax.

Credit: Ian Bradley

The central portion of M42, The Great Orion Nebula, showing the Trapezium. 8” Meade LX200R and Canon 750D, 6x30 second exposures at iso 1600. Credit: Ian Bradley

The central portion of M42, The Great Orion Nebula, showing the Trapezium. 8” Meade LX200R and Canon 750D, 6×30 second exposures at iso 1600.
Credit: Ian Bradley

EAS Newsletter for October 2020

Welcome to the October newsletter.

A pdf version of this member’s newsletter which includes an additional section on EAS business and developments is issued to all current members.

See also our monthly Sky Notes for objects observable in the sky from Kendal during this month.

It was good to ‘see’ people and chat at our first and, I believe, successful virtual meeting last month. We had an excellent tour of Graham Cornford’s observatory and a talk by Richard Rae on the Chinese Mars exploration missions. Some people stayed online at the end and had a chat which was nice. By the time you are reading this, you will either have received an email to give you the connection details for a talk by Sue Bowler on October 1st. I hope you can attend. We are also looking towards virtual meetings in November and December, the latter with Graham Fell’s legendary Christmas astronomy quiz. No pressure Graham!

With darkness now coming at a sensible hour, there is plenty out there to see. I’ve indicated some objects in the sky notes, but no doubt I’ve missed a few things! Winter is definitely near. I woke up very early this morning and was surprised to have a clear sky. On a brief wander out into my yard, I was greeted by a magnificent sight – Orion standing proud with Sirius twinkling on the horizon with the vivid orange Mars in the west and bright blue-white Venus in the east. Definitely a sight worth seeing.

It would be good to get a few more articles or photographs from members – please! – to add to the newsletter. Thanks to Moira, David & Richard for their contributions.

Clear skies.

Ian Bradley, on behalf of the EAS committee.

Astronomy News – David Glass & Richard Rae

We haven’t mentioned the discovery of phosphine in the atmosphere of Venus as a possible biomarker in this newsletter, because of the extensive media coverage – you probably know about it already. If you want more information, the most recent episode of The Sky at Night has a lot of detail about it and it should be available on BBC iPlayer. Here are a few other items of interest for this month…

OSIRIS-REx and Bennu

You may recall that a Japanese spacecraft Hyabusa-2 managed to touch down on an asteroid (Ryugu), grabbed some samples and is now heading back to Earth for arrival on 6/12/20. It is now the turn of a NASA spacecraft, OSIRIS-REx, to touch down on another asteroid, Bennu. The original touch-and-go (TAG) sampling of Bennu was scheduled for August 2020, but it is now scheduled for 20/10/20. The spacecraft has already been guided close to the surface in two practice runs and it mapped the asteroid in great detail, so there is a good chance that the chosen Nightingale landing site will work. Pressurised nitrogen will be used to “stir up” the surface and allow a target mass of 60g of material to be collected for return to Earth in 2023.

The target asteroid Bennu is somewhat different to Ryugu – it is just over half the diameter of Ryugu, and has a different composition. Both asteroids can provide valuable information about the materials involved in the formation of the Solar System and possibly in the development of life on Earth. Both NASA and JAXA (Japan Aerospace Exploration Agency) are collaborating on the research of these asteroids and are sharing methods and data.

For more details and a video showing what is planned, see NASA’s OSIRIS-REx

For a detailed summary of the spacecraft, what’s onboard and its mission, see OSIRIS-REx in depth.

OSIRIS-REx and its fairing for launch (credit: NASA/Glenn Benson)

Artist’s impression of OSIRIS-REx touching down on Bennu (credit: NASA’s Goddard Space Flight Center)

Starship and New Shepard Test Flights

Not much to report since SpaceX’s last “hop” to 500 ft, but plans are afoot for more test flights. Blue Origin were scheduled to test their latest New Shepard rocket on 24/9/20 with a new landing system for NASA, but this was scrubbed and no new date has been announced. The system has already been tested and flown to the edge of space, and one of its uses will be for space tourism to allow people to experience a few minutes in microgravity. It has also carried instruments and commercial payloads on suborbital spaceflights. For a video of the 8th autonomous test flight in April 2018 see here, although please don’t read the comments unless you like the “Carry On” films!

Blue Origin’s New Shepard booster and capsule (credit: NASA spaceflight.com)

As for SpaceX, they are currently preparing Starship SN8 for cryogenic testing, static engine firing and a launch. This time, there are fins…

An Extragalactic Exoplanet

Thanks to all the ground and space based projects to spot exoplanets in our galaxy, we know of over 4,200 of them (confirmed as present by two or more methods). However, there’s no reason why our patch of space should be unique. This is emphasised by a possible discovery of an exoplanet in another galaxy, M51 (the Whirlpool Galaxy – anyone photographed it?).

M51 from Kendal

This used a variation of the well-known transit method for detecting exoplanets, but in this case the exoplanet went in front of a bright X-ray source, instead of a star, back in 2012 and caused a dip in the X-ray brightness of the source. The exoplanet, catchily named M51-ULS-1b, is thought to be a little smaller than Saturn and is orbiting a binary stellar system consisting of a massive star and either a neutron star or a black hole. Accretion of matter from the star onto the compact object generates the X-rays. Because the X-ray source is so compact, the exoplanet completely blocked it for about 20 – 30 minutes, with a total time for the transit of about 3 hours. This is in stark contrast to the transit of exoplanets across whole stars, which only produce dips in optical brightness of about 1% or less.

The preprint paper (Di Stefano et al. 2020) with lots of information about the observations, the analysis (including the elimination of possibilities for such dimming other than exoplanets) and the implications of the findings can be found here: https://arxiv.org/pdf/2009.08987.pdf. The technique could open the door to the discovery of more such exoplanets in other galaxies hidden within archive images, so let’s see who takes up the challenge!

 

The region where M51-ULS-1b was detected in M51, the Whirlpool Galaxy. Left: an X-ray image from NASA’s Chandra X-ray Observatory showing the bright source within the galaxy. Right: an optical image from the Hubble Space Telescope of the boxed area on the left, showing the source at the edge of a star cluster within the galaxy (di Stefano et al. 2020).

The dip in X-ray signal when the exoplanet is thought to have passed in front of the bright X-ray source (di Stefano et al. 2020)

Four underground Martian lakes confirmed by new research?

It’s always great in science articles to make a fantastic claim that makes the headlines on the news. However, it is the dedicated hard work that goes on in the background that confirms or cast doubt on a previous theory that tends to go unnoticed. Here then is a recent paper published in Nature that helps confirm the presence of underground liquid water under the icy layered deposits at Mars` south pole.

A smaller data sample (just 29 observations) in 2018 suggested a sub-surface lake using radar data from the Mars Express space craft. See the 2018 report.

This new body of research September 2020 draws upon a larger data set utilising 134 observations between 2012 and 2019 and the detections indicate subsurface water in the region known as Ultima Scopuli.

Radar Map from the 2020 paper

The radar instrument onboard the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) was studied using techniques similar to those used to detect lakes under glaciers in Antarctica here on Earth.

The Martian underground lake measures 30 x 20km in size with 3 others detected that are 10 x 10km in size.

The science suggests these collections of water are extremely salty allowing them to remain liquid at very low temperatures. These lakes may be a remnant of the water that was once on the surface of Mars. To be sure they exist a mining expedition may be called for capable of drilling 1.5 km into the polar ice. Any volunteers?

Insight Investment Astronomy Photographer of the Year 2020

Feast your eyes on some of the highest-rated astrophotos in this prestigious competition. They are on display in London (details in the article). All are stunning, but one is tragic (you’ll see why).

Constellation of the month – Moira Greenhalgh

Hallo everyone. The constellation I have chosen this month is Pisces. I know, Pisces is best visible in November, but you will understand why now is important once I get to the end 😊

Firstly, finding Pisces is easy as it wraps itself around two sides of the great square of Pegasus

This is visible in a direction east-south-east late in the evening, moving further towards south-east and higher in the sky during the month. You notice that the ecliptic passes through the constellation, in fact the vernal equinox falls within the constellation (where declination 0 degrees crosses 0h).

Digression into the fanciful – it is therefore usually cited as first in listings of the signs of the zodiac. In the musical Hair when we celebrated the “dawning of the age of Aquarius”, we were actually in the age of Pisces and have been since 68 BC. The age of Aquarius starts around 2597 according to the IAU constellation description.

Pisces was one of Ptolomy’s original constellations, and has mythology dating from Babylonian times. I prefer the Greek story where Aphrodite and her son Eros dived into the sea to escape the monster Typhon. They tied themselves together so as not to get parted when they changed into fishes, as illustrated below.

Urania’s Mirror (1824)/Old Book Art Image gallery

This old depiction of the myth makes it very easy to remember the shape of the constellation, which is good as it is quite faint, having no stars under magnitude 3.0. It is easy to spot the asterism, the circlet of Pisces, which is the head of the lower fish, and the small triangle which is the head of the upright fish.

Considering individual stars:

  • α (alpha) Psc or Alrescha (arabic for the Cord) is the star that knots the two cords together, 309.8ly, has apparent magnitude 3.62
  • β (beta) Psc or Fumalsamakah (“mouth of the fish) is just off the circlet, 492ly, apparent magnitude 4.48
  • δ (delta) Psc, midway along the lower cord, 305ly , apparent magnitude 4.44
  • ε (epsilon) Psc (just to the left of δ above), 190ly, apparent magnitude 4.27
  • η (eta) Psc or Alpherg (“pouring of water”) halfway up the vertical fish, 349ly, apparent magnitude 3.62 is joint brightest with Alrescha
  • ο (omicron) Psc or Torcular (“thread”) 258ly, apparent magnitude 4.2 is just up the cord from Alrescha
  • and finally ω (omega) Psc 105ly, magnitude 4.03 is just before you reach the circlet.

Remaining stars are too weak for me to mention.

Deep Sky:

Messier 74 through Hubble. Image NASA

Just left of Alpherg (η Psc) is M74. This is a spiral galaxy showing many regions of star formation. A supernova was discovered in June 2003. The galaxy has an extremely low surface brightness, so you need a dark sky with good seeing conditions. November is recommended.

Hubble did not have any problem capturing a view.

3C31 is a radio source some 237 million light years from earth with jets caused by a supermassive black hole at the galactic centre extending several million light years in both directions.

Now back to the beginning, why should you be looking at this constellation now? You remember I said the ecliptic passed through the constellation? Well, ecliptic means PLANETS.

Mars is fast approaching opposition, where it will appear to us on Earth the largest we can see it until 2033, a big red/salmon ball, possibly surpassing Jupiter in brilliance. The diagram below shows the path of the planet through Pisces. It will appear at its largest around 3rd to 13th October. Do try to get out and look.

©Martin J Powell 2019 The Naked Eye Planets

More interesting to my way of thinking, is the planet Uranus shown in green to the left of the picture. It should be possible to line up on η (eta) Psc or Alpherg, and then track left to the wonderful methane blue/green dot. I read that it could be naked eye visible, but I’ll have my binoculars out, and failing that, the telescope. I have seen Uranus before but will take any chance I can get.

Recent Photographs

The Cocoon Nebula IC 5146 – exposure 170 mins. Credit: Ian Bradley.

The colourful double star Albireo, magnitudes 3.1 and 5.1, at the head of Cygnus. Credit: Ian Bradley.

The Eastern Veil Nebula supernova remnant in Cygnus. A three panel mosaic, each of 2 hours duration, combined in Pixinsight. Credit: Ian Bradley.

Mars, 17 September 2020.

Aurora from Long Meg stone circle and a bonus meteor. 00:30 September 26th. Credit: Carol Grayson.

The Ring Nebula M57 in Lyra. Credit: Ian Bradley.

Aurora, Long Meg and me. 00:30 September 26th. Credit: Ian Bradley.

EAS Newsletter for September 2020

A pdf version of this member’s newsletter which includes an additional section on EAS business and developments is issued to all current members.

See also our monthly Sky Notes for objects observable in the sky from Kendal during this month.

Barnard’s Star – Graham Fell

I thought I would write a piece on Barnard’s Star because I have heard of it but have absolutely no idea what it is. So, I’m sitting down at Wikipedia to learn about it and one of the joys of old age is learning something new. Where would we be if we knew it all? I apologise if you (the reader) already know everything about Barnard’s Star because with a newsletter you can just move on down to the next piece – unlike a real live lecture!

Now I know it is the 4th nearest known star after the three parts of the Alpha Centauri system and it is the closest star in the northern celestial hemisphere. It is a Red Dwarf which reminds me that during the lockdown, many episodes of another Red Dwarf were shown on TV so I could relive that great series from long ago. I even liked the new ones they did a couple of years back.

But – enough of this trivia – Barnard’s star is a red dwarf with a mass of only 1/7th that of our sun. Now that surprised me as I thought a red dwarf would be much more massive. Maybe one of our members could do a piece on Red Dwarfs and so explain to me why this star is so small! So, Barnard’s Star is not visible to the naked eye as it has a magnitude of about +9.5 but it is brighter in the infrared than it is in visible light.

Click to enlarge

 

This is a map of where it is and thanks to Wikipedia for the image on the left and Universe Today for the virtual sky image on the right.

 

It was named after an American astronomer in 1916 as he measured its proper motion of 10.3 arcsecs per year relative to the Sun and this is the highest known for any star. Here I’ve taken an animated GIF from Universe Today’s website showing its apparent movement. The movement is from 1985 to 2005 – so a 20- year period.

The apparent motion of Barnard’s Star against the background stars due to its proper motion. The images are roughly 5 years apart.

I am quite amazed to see a star move so much and one that is quite so close to us. It could be that its movement is due to the effect of Dave Lister having curries for breakfast! Dave Lister was only 3 million years old but Barnard’s Star is some 7 to 12 billion years old and so it could be one of the oldest stars in the Milky Way. It has lost some of its rotational energy but its brightness changes indicate a rotational period of 130 days compared to the 25 days of our Sun. With such a long age it was assumed that it would be quiescent in terms of stellar activity but in 1998 astronomers observed an intense stellar flare showing it to be a flare star.

One of the things that always amazes me is that in Astronomy, things are sometimes very different to what we expect. The whole history of astronomy is a universe of surprises every time we learn something new. (Look at what New Horizons found about Pluto!)

This star has roughly 150 times the mass of Jupiter but its radius is only 1.5 to 2 times larger, due to its much higher density. So, Jupiter is a tiny wispy cloud compared to Barnard’s star whereas I always imagine Jupiter as a massive planet thankfully picking up a lot of debris over the last 4 billion years and so saving our planet from death and destruction.

However, Barnard’s star gave us unexpected news in 2018 when an international team of astronomers announced the detection of a super Earth orbiting quite close to the star. Wikipedia tells us that ” was found near the stellar system’s snow line, which is an ideal spot for the icy accretion of proto-planetary the planet material” and this super planet orbits at 0.4AU every 233 days and has a mass of just over three Earths. With an estimated surface temperature of -170°C, it is not likely to be on Dave Lister’s list of planets to visit!

So, after this brief precis of the facts about Barnard’s Star, for which I thank Wikipedia, I can now bore people with all this information.

I am now looking forward to learning so much more – hopefully from members like me who decide to find out some information on one topic and share it with the Society. This short piece alone opens up topics like flare stars, red dwarfs, stars that move, snow lines etc.

New Horizons delivers again – Ian Bradley

You will know of the stunning results from the New Horizons probe from its passage by Pluto and the Kuiper Belt object Arrokoth. Well, it’s just got better… OK, I might be over-egging this!

You are probably aware that the distance to nearby stars can be measured using parallax. That is, the position of a nearby star appears to change relative to distance stars as the Earth orbits around the Sun, with it returning to its original position after a year. This is different to proper motion, in Graham’s article above, that is caused by the actual motion of the star so that the star never returns to than earlier position. Measuring this angular change, the parallax angle, from opposite sides of the Earth’s orbit gives, by simple trigonometry, the distance to the star as we know the Earth-Sun distance, 1 AU ≈150 million kilometres.

The problem is that these angular changes are tiny. The nearest star system to us is the Alpha-Centauri system (α, β and Proxima) is about 4.2 light-years away. For α-Centauri, the angle is only 0.74 arc seconds [symbol “], where 1″ is 1/3600 of a degree. For comparison, Jupiter is currently 45″ and the Moon 1800″ in diameter. The seeing due to the Earth’s atmosphere at the best observing sites on Earth is around 0.1″ and in Kendal is typically 1.5–2”, so you can see this is a formidable challenge requiring sophisticated image analysis. Hence the method only works out to a few hundred light-years for ground-based telescopes. However, being above the atmosphere, the Gaia satellite has measured stars out to 20,000 light-years from near-Earth orbit.

Click to enlarge

Proxima Centauri as simultaneously seen from the Earth and the New Horizons probe. The apparent position change against the more distant background stars is clear. Credit: New Horizons Collaboration

So, what’s new? New Horizons imaged two stars, Proxima Centauri, 4.2 light-years away, and Wolf 359, 7.9 light-years away, at the same time as they were imaged from Earth. The change in position of each star is really clear due to the different viewing perspectives – see the animated gif on the EAS website – and note that the change for Proxima Centauri is larger than that for Wolf 359, as Proxima Centauri is nearer to the Earth.

What’s new here is that New Horizons is 46 AU away from the Earth giving a much longer baseline and hence a larger apparent positional change of the stars against the background of very stars. Whilst this isn’t ground-breaking, and it is unlikely we’ll ever position a Gaia type survey satellite that far out in the near future, I still find this interesting.

Have a look at these two articles here and here.

BepiColumbo mission to Mercury – Graham Fell

Mercury has not been a major target for NASA, possibly because it is so close to the Sun and the fact that it spins so slowly on its axis. Its surface temperature varies from 427°C (which is twice as hot as your oven) to -173°C, which in our house is on the ‘nippy’ side.

As Mercury travels so fast around the Sun (24 to 30 miles per sec) a spacecraft has to be travelling pretty fast to get into an orbit. The Sun’s gravitational pull doesn’t help any deceleration needed to get into an orbit. Then Mercury has no atmosphere so aerobraking is of no use for any lander. So, more fuel is needed to land.

We’ve been there twice – Mariner 10 in 1974 and Messenger in 2012.

Now a third mission is on its way called BepiColumbo and it has two separate spacecraft:

  • The Mercury Planetary Orbiter (MPO) which will get images in several wavelengths to map the surface and exosphere composition. MPO provided by ESA.
  • The Mercury Magnetospheric Orbiter (MMO) will obviously study the magnetosphere and is provided by the Japan Aerospace Exploration Agency (JAXA)

Artist’s depiction of the BepiColombo mission, with the Mercury Planetary Orbiter (left) and Mercury Magnetospheric Orbiter (right) Source: Wikipedia

Hopefully, we will get answers to the following questions:

  1. What can we learn from Mercury about the composition of the solar nebula and the formation of the planetary system?
  2. Why is Mercury’s normalized density markedly higher than that of all other terrestrial planets, as well as the Moon?
  3. Is the core of Mercury liquid or solid?
  4. Is Mercury tectonically active today?
  5. Why does such a small planet possess an intrinsic magnetic field, while Venus, Mars, and the Moon do not have any?
  6. Why do spectroscopic observations not reveal the presence of any iron, while this element is supposedly the major constituent of Mercury?
  7. Do the permanently shadowed craters of the polar regions contain sulphur or water ice?
  8. What are the production mechanisms of the exosphere?
  9. In the absence of any ionosphere, how does the magnetic field interact with the solar wind?
  10. Is Mercury’s magnetised environment characterized by features reminiscent of the aurorae, radiation belts and magnetospheric substorms observed on Earth?
  11. Since the advance of Mercury’s perihelion was explained in terms of space-time curvature, can we take advantage of the proximity of the Sun to test general relativity with improved accuracy?

The mission was successfully launched on 20th October 2018 and is scheduled to enter orbit around Mercury in December 2025 and its primary mission will last for 18 months with a possible extension for one year.

The ESA-JAXA BepiColombo mission to Mercury lifts off from Europe’s Spaceport in Kourou. Credit: ESA

Finally, the Russians are proposing to launch a mission in 2031 to land on Mercury and it is called Mercury P.

The constellation of the month – Moira Greenhalgh

High up in the early September sky, slightly west of south, you will see the well-known Summer Triangle of stars, Deneb in the constellation Cygnus, Vega in Lyra, and Altair in Aquila

Source: EarthSky.org

Let us concentrate on Lyra, only a small constellation but worth learning.

The IAU has around 74 stars in the constellation Lyra, but there are six that are the clearest, a triangle with Vega at one corner, sitting on a parallelogram. Can you have corners in a triangle?

Source: baringtheaegis.blogspot.com

 

The mythology around the constellation refers to the lyre of Orpheus, The inspiration for lots of music. Did you ever sing the Vaughan Williams’ “Orpheus with his lute made the trees, and the mountain tops that freeze, bow themselves when he did sing”? Then there is the Gluck opera Orpheo and Euridice. Who could forget hearing Kathleen Ferrier singing the aria “What is life to me without thee, what is left if thou art dead”? I suspect I may be showing my age here.

Anyway, the story is that Euridice, wife to Orpheus the great musician, was bitten by a snake, died and was taken down into the underworld. Orpheus, distraught, followed her below, charmed Hades with his singing and was allowed to bring her back to the living world provided he led her out and didn’t look back until they were both outside. When he stepped from the underworld he did look, only she was still inside. Hades took her back and it was goodbye to Euridice. He went off on other adventures such as with Jason and the Argonauts where he saved them from the Sirens, but never looked at another woman apparently.

The constellation starting point is the star Vega (α Lyrae), the second brightest in the Northern sky after Arcturus (Sirius being in the Southern hemisphere) and, at this time of the year, it is the first star to pop into view as the sky darkens. Around 12000BCE Vega was the pole star, and will be again around 14000CE, give or take a couple of days. It is a main sequence star like the sun, and was one of the first stars to be photographed, and have its spectrum recorded. It even has a debris disk around it similar to our Kuiper Belt. Sheliak (β Lyrae, bottom right of the parallelogram) is a binary system with the material being transferred between the stars. Beta Lyrae type variables are named after this star. Sulafat (γ Lyrae) is a blue giant and the second brightest star in the constellation.

Source: Torsten Bronger CC BY-SA 3.0

Forming the small triangle with Vega are ζ Lyrae, a wide binary, and ε Lyrae also a wide binary, said to be naked eye separable. Good luck with that! Both components of epsilon are themselves binaries, hence the name “double double”. A small fifth star has also recently been found, so I don’t know what that makes the system “double double single” or “double treble”. Sounds like crochet stitches to me.

The final star of the parallelogram is δ Lyrae, an optical double and part of the sparse faint delta Lyrae cluster. Outwith the parallelogram are κ and θ Lyrae, a red giant and orange giant. Very faint are many other doubles and variables of different colours.

Lyra has many many deep sky objects, of which M57 and M56 are the most well known. M57, the ring nebula, a planetary nebula, looks wonderful in a professional telescope. For an amateur it looks like this below, not coloured but definitely a ring.

 

Credit: Hubble Heritage Team

M56 (right) is a globular cluster and not visible to the naked eye.

Credits: NASA & ESA

The constellation Lyra was within the Kepler mission’s field of view, and many exoplanets have been found, including the 5 planets orbiting Kepler-62 of which at least 2 are within the habitable zone and are likely rocky earth like planets.

Astronomy News – David Glass

Betelgeuse – Still a Puzzle!

Ok, in our last newsletter we reported on a study using the ALMA telescope which indicated giant sunspots as the cause of Betelgeuse’s dimming earlier this year. If only that was the last word – but it isn’t. A new study using the Hubble Space Telescope is pointing towards a different cause, namely the ejection of a giant ball of hot plasma from the surface of the star. Betelgeuse got brighter at ultraviolet wavelengths during this time. This ball of plasma cooled, and dust condensed within it which blocked the light from the star and caused the observed dimming. Observations at ultraviolet wavelengths over time indicated that the plasma was ejected late in 2019 at quite a speed (200,000 mph), and the dimming started about a month afterwards. Here’s a preprint of the paper describing this, which is now published in the Astrophysical Journal.

Artist’s impression (ultraviolet wavelengths) of what might have happened to Betelgeuse late last year. First two images: a blob of hot plasma is emitted from a giant convection cell. Third image: Dust condenses out of the blob as it cools. Fourth image: view of the dusty cloud as seen from Earth.

All images Credit: NASA, ESA, and E. Wheatley (STScI).

And just as things looked like they’ve returned to normal, Betelgeuse appears to be dimming again. Photometry obtained from STEREO-A (Solar Terrestrial Relations Observatory spacecraft), at a time when Betelgeuse can’t be observed from the ground, showed a drop in V-band brightness of about 0.5 between mid-May and mid-July this year. The extent of the dimming is similar to a periodic dimming that happens, but is earlier than expected. You can read the bulletin announcing these findings here.

V-band magnitudes for Betelgeuse over time. The green and blue points are from ground-based telescopes. The red points are from the STEREO spacecraft. The gaps in the ground-based data are times when Betelgeuse is not visible.

Looking at the red points on the right, Betelgeuse is fainter now than it was in mid-April (Dupree et al.)

SpaceX Starships

Following on from the successful “hop” of Starship SN5, Spacex put the next one (imaginatively called SN6) into position at Boca Chica, Texas, fitted a Raptor engine to it and lit it on 23/8/20.

Test firing of Raptor engine on Starship SN6 (credit: SPadre.com via Twitter)

It is possible that SN6 will do a “hop” to about 500 ft as early as the end of August, so keep an eye out for footage! SpaceX is evolving the rocket in small steps. SN7 could be pressure-tested until it bursts and SN8 could have three raptor engines fitted to achieve an altitude of 12 miles. However things proceed, we can expect to see dramatic tests and higher “hops” with more engines in the near future!

(Tiny) Asteroid heading for Earth

Hopefully, you saw the word “tiny” and aren’t digging your underground bunker and stocking it with bottled water and spam to last 7 years. To coincide with the presidential election in the USA on November 2nd, a wee asteroid (2018 VP1) could intercept the Earth. Or not. There aren’t enough observations yet to be certain, and the odds are about 0.4% that it will hit the Earth. This tiddler was first picked up by the Zwicky Transient Facility at the Palomar Observatory (Southern California). It’s an Apollo asteroid, which has an elliptical orbit which crosses Earth’s and an orbital period of about 2 years. It is thought to be about 2m across. The asteroid that put in a spectacular performance seen from Chelyabinsk in 2013 was thought to be about 20m across, so 2018 VP1 isn’t a cause for concern. But it could make a nice trail as it burns up, so let’s keep an eye on forecasts just in case there’s a slim chance that we can catch it!

The observations and the orbital parameters used to estimate the asteroid’s position can be found here  – click on the Orbit Diagram to see how the asteroid could behave.

I was going to include an image of an asteroid hitting the Earth, but I don’t want to start anyone off digging bunkers! Oh, go on then……

2018 VP1 would be too small to see in this artist’s impression. Credit: ALAMY

Giant halo around the Andromeda Galaxy

It’s been known for a good while that late-type galaxies (star-forming, with spiral structure) contain interstellar medium (ISM), i.e. gas and dust between the stars. This is the raw material for the formation of new stars (and planets!), and is also the exhaust from old stars as they evolve and die. However, the ISM doesn’t just stay in the galaxy. It can get ejected (e.g. by supernovae) and fall back in later, extending the timescale over which new stars are formed. A recent study looked at this circum-galactic medium (CGM) around the Andromeda galaxy (M31) using the Hubble Space Telescope. The CGM is so rarefied that it hardly emits anything that can be detected, but it can obscure light from bright objects behind it – in this case, the ultraviolet light from quasars. The study found something amazing – the cloud of CGM around M31 is huge, extending over 1.3 million light-years from the galaxy centre. This is about halfway to our own Milky Way galaxy. If we could see it, it would have a greater diameter than the Plough in Ursa Major. The study also found structure within the CGM that could indicate how it formed and is evolving. You can read the preprint of the paper (now published in the Astrophysical Journal).

If we could see the circumgalactic medium around M31, here’s how it might look. (Credits: NASA, ESA, J. DePasquale and E. Wheatley (STScI), and Z. Levay (background image)

Our own Milky Way probably has a similar CGM halo. We know that M31 and the Milky Way are heading for each other and will collide in billions of years hence – however, if both galaxies have massive CGM haloes then perhaps they are starting to interact already!

EAS Newsletter for August 2020

What’s in the sky this month

For ISS passes, the Moon, the planets, comets, meteor showers and Sky Charts for this summer see our Sky Notes page.

Astronomy News July 2020 – David Glass

Space X

SpaceX have managed two spectacular achievements very recently. The first (2nd August) was the safe return of the two astronauts who went up to the ISS in Crew Dragon at the end of May. This involved a traditional “splashdown” which we haven’t seen in a while! All went well and the astronauts are safely back on Earth. A full replay of the whole event with very informative commentary is available here (You can use the scrollbar to zoom through the quiet bits!)

 

Credit: NASA

The second was the successful “hop” made by Starship SN5 (4th August local time). A single Raptor engine fuelled by liquid methane and liquid oxygen pushed the 60 tonne, 30m tall assembly gradually into the air and brought it down safely again. Some nice clips of the event are here, the second of which shows the leg deployment and the engine in action (although the flames on the side don’t look like they’re supposed to be there)

The assembly included a “mass simulator” on top to represent a payload.

Credit: @austinbarnard45

Watch out for further “hops”, and later on a much higher altitude flight! It looks like field-fabricated rockets can be made to work after all.

SN1987A

Supernovae are rare beasts, but if they happen close enough to us then they can be studied in detail to see how they play out. The results can be compared with models, and teach us a lot about the physics involved. A relatively close one happened in the Large Magellanic Cloud (about 170,000 light-years away) in 1987 and is imaginatively called…wait for it…SN1987A.

For context, the Large Magellanic Cloud with the Tarantula Nebula and SN1987a in 1987. Credit: ESO

It’s long been suspected that a small but massive neutron star should have been left at the centre of the event, but nobody had been able to prove it. However, a recent paper shows that a hot dusty “blob” at the heart of the region is likely to be heated by a neutron star (given the equally catchy name NS1987A). Observations were made with ALMA, a multi-dish interferometric telescope in the Atacama desert, Chile (altitude 16,000 ft), the “How ALMA Works” page is useful. This is a great opportunity to study the early evolution of a supernova, and the results of this study confirm a suspicion that the explosion was asymmetric, with more material blasted out in one direction than the other. No doubt more studies are on their way!

SN1987A remnant, imaged by the Hubble Space Telescope in 2010. The ring is about 6 trillion miles across, and is cause by a shock wave from the event impacting the material in the region. The blobs will merge over time to form a solid ring. (credit: NASA)

There is a lot more on this topic here. In a nutshell, the observations detected a warm ‘blob’ at the expected location of the neutron star. Theoretical modelling indicates that the most likely scenario is that there is a hot (5 million degree) non-spinning neutron star warming the dust.

Extremely high-resolution ALMA images revealed a hot “blob” [red] in the dusty core of Supernova 1987A (inset), which could be the location of the missing neutron star. The green represents the glow of visible light, captured by NASA’s Hubble Space Telescope. The blue colour reveals the hottest gas and is based on data from NASA’s Chandra X-ray Observatory. Credit: ALMA (ESO/NAOJ/NRAO), P. Cigan and R. Indebetouw; NRAO/AUI/NSF, B. Saxton; NASA/ESA

Nova Reticuli 2020

I know that travel to the Southern hemisphere is challenging right now, but people there can witness a nova (Latin: nova stella or “new star”). This was found by a comet-hunting astronomer. More detailed observations indicate that this object is a “classical nova”. These occur when a white dwarf star is in a binary system with a larger star, and the white dwarf accretes matter from its larger companion. Eventually, the mass of material built upon the surface of the white dwarf reaches a critical mass and undergoes a thermonuclear explosion creating the nova, but crucially leaves the white dwarf intact. Classical novae can therefore happen more than once. A more extreme case is a Type Ia supernova, where the mass buildup causes the whole white dwarf to be destroyed.

Artist’s impression of a white dwarf accreting matter from a companion star, triggering a thermonuclear explosion (credit: K. Ulaczyk / Warsaw University Observatory)

Solar Orbiter

Closer to home, the Solar Orbiter mission sent back some remarkable images of the Sun in July. The mission is intended to study the Solar wind and other important topics related to the Sun. These images are taken from the closest distance yet achieved (48 million miles), and were meant to be tests of the instruments. However, the images found numerous hot spots within the Solar corona which are now named “campfires”. These appear to be like Solar flares but are at least a million times smaller. Perhaps this new discovery can help explain at long last how heat energy is transferred to the Solar corona, which is a region above the visible photosphere (at 5,800 K) but is at a temperature of over a million Kelvin. This problem has baffled Solar physicists for a long time! An animation of the observations is here:

The observations are at extreme ultra-violet wavelengths (17 nanometres), associated with very hot material at around 1 million Kelvin.

Who is and isn`t going to Mars? – Richard Rae

Why have there been so many missions to Mars over the last few weeks?

I don’t know about you, but I have noticed throughout the summer there have been numerous missions to Mars announced on the media; a bit like buses, none for ages then several come around the corner all at once!

Let’s have a look at the recent missions and why there has been a spate of Martian orientated activity this July. Also, we will discover some rovers missed the bus completely and we will answer the question; how many years have elapsed since the Curiosity rover landed on Mars?

What does this image tell us?

The route Perseverance will take to Mars. The alignment of the orbits allow travel to Mars in ~6 months (TCMs mark changes to the path of the spacecraft) Credit: NASA

Once every 26 months, the Earth and Mars are positioned in their respective orbits in such a way that it reduces the travel time and minimises fuel spent, allowing spacecraft to travel to Mars in roughly 6 months. In the diagram above you can see Mars is playing catch-up as the spacecraft move outward toward the orbit of the red- planet. The last few weeks have therefore been the optimal time for launching missions to Mars.

Nasa and China are sending roving vehicles to the planet this summer. The United Arab Emirates have also launched a mission to Mars. However, the European Space Agency`s (ESA) mission consisting of its rover named Rosalind Franklin has been cancelled.

In March this year the ESA project was called off due to further testing requirements of both software and hardware. The ESA project ExoMars mission (Exobiology on Mars) jointly with Roscosmos (the Russian space agency) is simply postponed for a further (as you have now guessed) 26 months. The project is now named ExoMars 2022.

Here is Dr Anna Nash AIT & Contamination Control Engineer holding up the ESA Pan-Cam at its working height, after giving a bio-safety lecture at Astrofest this year. (Ok it’s not the actual rover camera but an engineering model)

Curiosity is the current rover that Nasa has on Mars.

Nasa`s rover Curiosity touched down on Mars eight years ago on 5th Aug 2012 and will now soon be Joined by the recently launched rover Perseverance. Credit: NASA

Curiosity landed on the surface of Mars eight years ago; I had to double check this date I cannot believe that it was that long ago. It has travelled 14 miles on the planet, drilling 26 rock samples along its way. The data Curiosity collects is helping to picture how the Martian climate changed over millions of years and why all the streams have dried up. There are globally over 500 scientists involved in this project so I am sure you can see the interest in getting a larger more sophisticated rover onto the planet’s surface.

Curiosity will shortly be joined by the Perseverance rover, so another sky crane landing is destined to take place in February 2021. You can follow the mission (simply named Mars 2020) from here including real-time flight telemetry, and a Helicopter is included…

Ingenuity is the name of the helicopter that will travel with Perseverance to Mars. Primarily this will be a demonstration of technology mission attempting the first autonomous powered flight on Mars. Many further details of this amazing development are available.

UAE first inspiring mission to Mars

The United Arab Emirates successfully launched the Hope probe from Japan. The UAE engineers assisted by American scientists have produced a sophisticated satellite in just 6 years. This will orbit Mars and investigate the planet’s atmosphere. https://www.bbc.co.uk/news/science-environment-53394737

Launch of Hope on July 19, 2020 from Japan’s Tanegashima Space Center on a Mitsubishi H-IIA rocket. Credit: Mitsubishi Heavy Industries

An artist’s impression of the UAE Hope spacecraft in orbit around Mars. Credit UAE Space Agency

Chinese Mission Tianwen-1 a most comprehensive mission

Finally, the Chinese have a mission named Tianwen-1 that will include a lander an orbiter and a rover. This combination of craft including 13 scientific payloads, has never been attempted before. If successful it will herald a major technological breakthrough. The aims here are to extensively survey the entire planet with the orbiter and to send the rover to areas of high scientific interest. See here.

Tianwen-1 Rover Instrumentation including a radar to detect possible pockets of sub surface water.

There is a short article in Nature regarding this ambitious mission. So, you now have an overview of the missions on their way to Mars, I am sure 2021 will be an exciting year in the exploration of the red planet. Keep checking the mission web pages to keep up with developments

Stellar signposts News – Ian Bradley

As the skies are now getting darker in the evening, it is worth refamiliarizing yourself with the layout of the sky to help you find interesting objects. My constellation navigation skills are not that good having, for many years, used GoTo telescopes. If like I do, you generally observe from one place, in my case my backyard, you also develop intuition as what major constellation are about and where they are. But when you go to a new place…

Until the advent of laptops and planetarium software, my default star atlas was Norton’s Star Atlas. It has clear charts of stars down to magnitude 6.5 and many interesting objects – Messier objects, variable stars and double stars for example. It also includes concise information on many astronomical terms and concepts so the atlas is a useful astronomical quick and simple reference document. For star charts, The Cambridge Star Atlas does a similar job although personally I prefer Norton’s.

With smartphones, there are many apps [SkySafari, Stellarium…] to tell you what is where [especially so if your phone has a GPS and compass built in], and provide information on objects but the small screen size is very limiting.

So, what are the alternatives? It’s dark, your mobile is low on power… We come back to the stars themselves. For the beginner, identifying a few of the major constellations can provide great signposts to less familiar ones, and from them to that small faint fuzzy nebula…

The first thing we have to do is orient ourselves correctly. We are lucky in the northern hemisphere to have a star close to the celestial north pole. At magnitude 2, although its brightness varies between 1.86 and 2.14 over a 4-day period, it is relatively obvious and although not particularly bright, there are no bright stars round about it that can lead to confusion.

Stars rotating around the north celestial pole – a 38-minute exposure from Kendal looking along the River Kent. Polaris is the obvious bright star just below the centre of rotation.

The easiest way to find Polaris is to spot the asterism of the Plough (aka The Big Dipper or The Saucepan) in Ursa Major. This is circumpolar and so always visible. It is fairly unmissable and once you’ve tuned in on its shape, you can recognise it even when much of the asterism is covered by cloud. The two stars at the side of the saucepan are known as The Pointers. Once you’ve found The Plough, finding Polaris, and thus north, is easy. Just follow the line of the two pointer stars away from the bottom of the saucepan, and you come to Polaris.

Bear in mind that at different times of the night, the saucepan will be oriented differently. Twelve hours later than the time in the graphic, the saucepan is ‘upside down’ and you have to follow the pointers down to get to Polaris.

 

The Plough is a great signpost to other constellations too with the advantage that it is always visible, that is circumpolar, from our latitude.

It is fairly straightforward from The Plough to find Arcturus in Bootes from the curve of the saucepan handle, the tail of the bear, and if you continue the curve, you will come to Spica in Virgo. Along the line opposite to the pointers gives you Deneb in Cygnus in one direction and Regulus in Leo in the other. One diagonal points to Gemini and the pan top to Capella in Auriga.

Cassiopeia is another obvious constellation which can help you navigate, and again has the advantage of being circumpolar. The obvious W of stars open towards the pole star is familiar to most of us.

Finally, although it won’t really be visible until rather late in the evening in the autumn months, there is the magnificent Orion.

I hope this will help you to quickly find your way around. Once you’ve found the major constellations, you can then, in conjunction with your favourite star chart or app, find the less obvious ones. Good luck.

Right-angle polarscope viewer – Ian Bradley

Following on from David Glass’s suggested project in last month’s newsletter, I can report that I tried it.

I had a Canon Right Angle Finder C in my loft. I bought it many years ago when I was imaging with my Canon 400D on my Meade 8” telescope and frankly, I was unimpressed by its usefulness, hence its sojourn in my loft!

I was thinking of trying David’s project as polar aligning was always a pain, metaphorically and physically. Too many times awkwardly peering through a polarscope. On looking to source a right-angle finder, the penny dropped that I had one in the loft.

I used it to polar align my Skywatcher Adventurer tracking mount – see the picture of Comet Neowise later on in the newsletter. I subsequently needed to add more of the furry side from a velcro strip as it didn’t fit snugly enough. I made another minor modification to the design in David’s article – my finder had four tiny screws attaching the scope to an adaptor plate that fitted my camera eyepiece. The adaptor made a perfect template to drill the four small holes in the film canister, so that’s what I did.

The assembled viewer. The 4 screws, the furry Velcro and the removed adaptor plate can be seen in the photograph on the right.

Would I do anything differently if I did it again?

Yes. I started the large hole in the end of the film canister with a largish drill and then cut it to get the correct clearance. The plastic tends to deform when drilling and the following cutting is so hit and miss. Instead, I’d use a hot soldering iron, or similar, to melt the plastic and create a much tidier and better fit.

Thanks David – hopefully I’ll have less cricked necks now.

Recent Photographs

M5 in Serpens. Imaged from Kendal. Credit: Ian Bradley

Sharp eyes readers will spot that this is a different image from that in the last newsletter – the editor apologises for the wrong photograph!

Comet Neowise from Kendal Castle July 20th, 00:53. Nikon D7000, 35mm ISO1600 4sec at f3.5. Credit: Ted Woodburn

Comet Neowise from Kendal Castle July 20th, 00:43. Nikon D7000, 35mm ISO1600 6sec at f3.5. Credits: Ted Woodburn

Comet Neowise from Kendal Castle July 20th, 00:24. Nikon D7000, 24mm ISO1600 3sec at f3.5.

Comet Neowise from Bradleyfield, Brigsteer Road, Kendal July 16th, 23:47. Nikon D7000, 200mm ISO1600 2.5sec at f4. Credit: Ted Woodburn

Comet Neowise from Orton Scar, July 11th, 23:34. Canon EOS 750D, 35mm ISO800 3 x 6sec at f5. Credit: Ian Bradley

Comet Neowise from Orton Scar, July 11th, 23:27. Canon EOS 750D, 150mm ISO400 64 x 4sec at f5. Individual untracked images aligned on both stars and comet and then stacked and combined.

Comet Neowise from Troutbeck, July 13th, 23:43. Canon EOS 750D, 33mm ISO6400 3.2sec at f4.5. A frustrating night dodging cloud. The people trying to sleep in their camper vans on Kirkstone were probably not too pleased with us being there! Credit: Ian Bradley

 

Comet Neowise from Kentrigg, Kendal, July 19th, 23:43. Canon EOS 750D, 77mm ISO800 4 x 1min at f4. Camera on a Skywatcher Adventurer tracking mount – its first use. Individual images aligned on both stars and comet and then stacked and combined.

Despite light pollution from Burneside, both the bright dust tail and the faint ion tail are visible. Credit: Ian Bradley

EAS Newsletter for July 2020

What’s in the sky this month

For Noctilucent Clouds (NLC), ISS passes, the Moon, the planets, comets, meteor showers and Sky Charts for this summer see our Sky Notes page.

Astronomy News July 2020 – David Glass, Richard Rae & Ian Bradley

Space X and Dragon launch

Dragon crew ship Endeavour docked with the ISS. This photo was taken on June 30th by NASA astronaut Col Doug Hurley whilst on a spacewalk. Credit: Twitter feed Col Doug Hurley@ Astro_Doug
Click the image for a full-page view

SpaceX made history with the launch of NASA astronauts aboard Spacex’s Dragon vehicle for a visit to the ISS.

The last weekend in May marked a turning point in frontier space history. A private company is now providing a “taxi service” to transport astronauts to the International Space Station. SpaceX has successfully delivered 2 astronauts. I hope you were all glued to the live NASA news feeds watching this significant event unfold. Sole dependence on the ageing Russian Soyuz capsules launching from Kazakhstan system is now a thing of the past.

To put this in perspective, the last astronaut to be launched from America was nearly a decade ago in 2011 with the space shuttle. Previously SpaceX has successfully sent un-manned flights to the space station in 2019 using automated docking procedures.

SpaceX transport system for crew and cargo will now be a gamechanger in this rapidly developing industry.

SpaceX (again)

Following on from the spectacular Crew Dragon launch and rendezvous with the ISS, our attention turns back to the Starship project. You’d think that they would have learned something from their high-profile failures – well it seems they might have. Starship SN5 has apparently passed a full cryogenic proof test on 30/6 and is now being fitted with a Raptor engine for further tests.

Earlier, a section of SN7 was tested to destruction. Whether this was intentional wasn’t known at the time. This a classic example of a quasi-instantaneous release of pressurised cryogenic liquid.

Keep an eye out for live coverage of engine testing and any other tests that happen. There are some lively amateur YouTube sites that provide running commentary from their own webcams on nearby apartment blocks trained on the testing site. Here is one with an informative running commentary, local insight and buzzing live chat.

Betelgeuse (Again)

You probably remember the dimming event that affected Betelgeuse last Winter. At the time, everyone thought that the star had coughed out a cloud of dust that caused it to dim at optical wavelengths. It turns out that it was probably giant “starspots” instead. A team used observations at sub-mm wavelengths to investigate what had happened. They found that Betelgeuse dimmed by around 20% at sub-mm wavelengths, which is much more than could be achieved by external dust. The dimming must therefore have been caused by large cooler patches in the star’s photosphere, possibly covering 50 – 70% of the star’s surface.

Here’s a link to the paper describing the results.

The “Missing Link” Between Neutron Stars and Black Holes

It’s been known for a while now that when massive stars end their lives as supernovae, they can leave behind either a neutron star or a black hole. However, no neutron star with mass greater than 2.5 times the mass of the Sun has been found, or no black hole with mass less than 5 Solar masses. There is a gap in mass which nobody understood. However, in August 2019 the LIGO gravitational wave observatory detected an object with a mass of 2.6 Solar masses, as it merged with a more massive black hole. No optical counterpart to the event was detected. here is the paper for this discovery (click on the pdf button).

They conclude “we cannot firmly exclude the possibility that [the less massive object] is a neutron star, nor can we be certain that it is a black hole”.

Pluto and its Sub-Surface Ocean

Montage of enhanced colour images of Pluto (bottom left) and Charon, from the New Horizons spacecraft. (NASA/JHUAPL/SwRI)

Montage of enhanced colour images of Pluto (bottom left) and Charon, from the New Horizons spacecraft. (NASA/JHUAPL/SwRI)
Click the image for a full-page view

The spectacular images of Pluto sent back by the New Horizons spacecraft were just the start. Based on the data received, there is now evidence of a liquid water ocean underneath Pluto’s crust. A team examined the images for signs of stretching or compression, which is what would happen if a sub-surface liquid ocean were to freeze because ice expands when it forms. However, nothing was found even in the oldest terrains, implying that sub-surface water is in a liquid state. This and other key findings are explained if Pluto formed hot within a few tens of thousands of years, and maintained its internal heat through collisions. Sub-surface oceans on planets (dwarf or otherwise) and moons are potential locations for extraterrestrial life, and therefore attract a lot of interest. The paper is behind a paywall , but the abstract is worth a read.

 

Remote Observing with the IRAM 30m Telescope – from Windermere

After poor weather during my last trip to the IRAM 30m telescope in Spain, I was given more time to observe. However, because of Covid-19 travel restrictions, I had to do this remotely from Windermere…

This worked very well, and I managed to get everything observed for my project during the last week of June. I also invited another postgrad student to join in remotely from Preston, to get the experience of observing with this telescope. I’m very grateful to the folk at IRAM, Granada for getting the telescope operational again after the Covid-19 crisis.

Centaurs – Richard Rae

I am sure we were all intrigued to hear about extra-solar system visitors to our solar system such as the interstellar object Oumuamua that was discovered floating through our patch of space in 2017. However, would it not be quite the discovery to find we have had “visitors” from afar joining our solar system many millions of years ago!

Centaurs are small intriguing objects that have orbits that cross those of the outer planets.

New research examining the past orbits of these Centaur objects focuses on their origin and whether or not they could have been present at the formation period of our solar system. The paper by Fathi Namouni (Observatoire de la Côte d’Azur, France) and Maria Helena Morais (Universidade Estadual Paulista, Brazil) suggest that 19 obects have been captured by our solar system that were previously orbiting other stellar systems.

Who would have believed we had so many interstellar objects within our midst?

For the full MNRAS paper click this link.

Neutrinos from the Sun confirm stellar physics theory – Ian Bradley

For many years, the lack of the expected neutrinos from the Sun puzzled astrophysicists. In the 1960’s, Ray Davis’ huge tank of cleaning fluid detected far fewer neutrinos than expected.

The Borexino experiment, Gran Sasso, Italy. A researcher stands in a spherical vessel that 278 tonnes of liquid hydrocarbons Credit: Volker Steger/SPL

The Borexino experiment, Gran Sasso, Italy. A researcher stands in a spherical vessel that 278 tonnes of liquid hydrocarbons Credit: Volker Steger/SPL

Neutrinos are released by fusion reactions inside the core of stars and provide a direct way to measure those processes. They are extremely difficult to detect despite thousands of millions passing through your fingernail each bsecond. The rate of neutrinos detected from the Sun, indicates the rate of fusion inside the core of the Sun. Davis’s experiment only measured 30% of the expected rate. That problem was solved when it was discovered in the early 2000’s that neutrinos can change in their passage from the Sun to detectors on Earth into ones the detectors couldn’t detect. Detectors have improved enormously, both in efficiency and size, since Ray Davis’s day.

nside the core of the Sun, the main fusion process is 4 protons fuse together (in a multistage process) to produce helium and energy [plus two neutrinos]. This proton-proton chain reaction dominates in low mass stars like our Sun. In higher mass stars, a different process dominates – the carbon-nitrogen (CN or CNO) reaction. The nett result is the same, 4 hydrogen nuclei fuse together releasing helium, energy and two neutrinos. In stars like our Sun, the core is too cool for this process to be dominant and only about 1% of the Sun’s energy is produced by this process.

However, the new detectors have allowed this weak process to be detected despite the high background from p-p chain neutrinos. This detection confirms for the first time the decades- old theoretical predictions that some of the Sun’s energy is made by this process and that our understanding of the fundamental fusion processes is correct. More details in this full article [free].

A simple project: a right-angle polarscope viewer – by David Glass

Some of us at least have had the joy of trying to use a polarscope to align a telescope at our latitude. I don’t know anyone with a sufficiently flexible neck or back to do it properly. The solution – make a right-angle viewer. A good recipe is here.

…and I thought I’d give it a go.

I managed to get an old Pentacon (East German) right-angle camera finder on Ebay – it was grubby but it cleaned up very well. I then cut up an old 35mm film canister and made a shaped slot at the back to fit the adapter – and voilà! No more wet/dented knees and sore neck. The viewer is not that heavy and doesn’t affect the polarscope. The film canister provides a snug fit and can be removed without harming the polarscope.

Making a right angle viewfinder for a Skywatcher Star Adventurer camera tracker (Image Credit: David Glass)

Making a right angle viewfinder for a Skywatcher Star Adventurer camera tracker Image Credit: David Glass

Recent Photographs taken by Ian Bradley EAS

The Eagle Nebula, M16 and the Pillars of Creation. A real challenge as always less than 20 degrees maximum altitude from my backyard and directly over central Kendal on 31st May.

The Eagle Nebula, M16 and the Pillars of Creation. A real challenge as always less than 20 degrees maximum altitude from my backyard and directly over central Kendal on 31st May.
Click the image for a full-page view.

This shows just how short the night is at the end of May. The sky brightness was measured using data from the same imaging run used for the picture of M16. The detected brightness in a region with no stars was measured. Pre-dawn is seen by the rapid brightening around 0230. Only date from within the blue region was used to create the M16 image.

This shows just how short the night is at the end of May. The sky brightness was measured using data from the same imaging run used for the picture of M16. The detected brightness in a region with no stars was measured. Pre-dawn is seen by the rapid brightening around 0230. Only date from within the blue region was used to create the M16 image.

The Crescent Nebula in Cygnus powered by a Wolf-Rayet star. Imaged from Kendal.

The Crescent Nebula in Cygnus powered by a Wolf-Rayet star. Imaged from Kendal.
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M61 in Virgo with supernova SN2020jfo indicated on May13th. This supernova was first detected May 6 2020, so a week earlier. Imaged from Kendal.

M61 in Virgo with supernova SN2020jfo indicated on May13th. This supernova was first detected May 6 2020, so a week earlier. Imaged from Kendal.
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Globular cluster M13 in Hercules. Imaged from Kendal

Globular cluster M13 in Hercules. Imaged from Kendal.
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M5 in Serpens. Imaged from Kendal.

M5 in Serpens. Imaged from Kendal.
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M10 in Ophiuchus. Imaged from Kendal

M10 in Ophiuchus. Imaged from Kendal.
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M12 in Ophiucus. Imaged from Kendal.

M12 in Ophiucus. Imaged from Kendal.
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