Welcome to the April 2021 newsletter. Not a lot to say this month. Our virtual Zoom programme continues and the weather continues to not play fair. I guess that is one downside of living in Cumbria.

There has been auroral activity recently although for the best nights we were clouded out. As I write this, the reduction in restrictions due to coronavirus are imminent, so you should be able to travel a little bit further to get some darker skies. If the auroral alerts go off [e.g. Glendale Skye auroral alert phone app, or the aurora-service.eu website is predicting in its 3-day forecast that activity is going to be 5 or above, then get out and have a look if the Solar wind gauges Bz [left gauge] is negative [in the amber or red].

Other news, there is a binocular nova visible in Cassiopea, more on this later.

Our next meeting is this coming Thursday, April 1^st, with Hannah Sargeant from the OU talking on ‘The Hunt for Lunar Water’. Our May meeting is Dr Dimitris Stamatellos from UCLAN speaking on Faraway worlds: Exoplanets and planet formation. I hope to see you these.

Finally, we hope everyone is keeping well.

Ian Bradley, on behalf of the EAS committee.

Astronomy News – David Glass

SpaceX

Just after the last newsletter was published, SpaceX managed to launch its Starship SN10 to an altitude of about 10km, and managed to land it – for a short while anyway. For a very good replay of events on 3/3/21, see here (LONG VIDEO!) And zoom forward to about 10^h 20^m. Don’t stop watching after the landing, there’s a surprise coming at 10^h 34^m! The commentary will keep you engaged until then.

If you’ve seen the video, you will have seen the recently landed (but not quite vertical) starship suffer an internal explosion and jump back into the air again for another (and more destructive) landing. You may also have seen a fire in progress in the engine area just before landing, which seemed to continue after landing. Is this connected with the explosion? The outside of the lower part of the rocket looks like it’s still frosted up after landing, which means that there is still cryogenic liquid methane (flammable!) on board. Although the storage tank is made of stainless steel, it is very thin-walled and it is possible that the fire might have weakened it. Or, the tank may have been damaged on impact. Or, the non-upright landing may have damaged pipework around the engines leading to a methane leak which then built up a flammable gas cloud around the engines. Whatever the explanation, the result was an unscheduled re-launch.

In spite of the dramatic turn of events, the flight was successful in many ways including the first upright landing of a starship. Next, SN11 was wheeled out for positioning on a launch platform on 7/3/21. After two static firings of the engines (the latter requiring an engine change), SN11 was awaiting a final static fire test before launch. As I’m writing I have the live feeds running from LabPadre and NASASpaceflight running – the final static firing has just happened (13:09 GMT 26/3/21), and there is a lot of anticipation for a launch today. Almost everything is in place – the road is closed, the launchpad is clear, Temporary Flight Restrictions (TFRs) and Notices to Mariners are in place. And so we wait…Nope, it’s been scrubbed for today! Monday 29/3 is a possibility, so tune in and see.

If you want to drop in on the Boca Chica facility at any time and see what’s going on, try: LabPadre’s Nerdle Cam which also has a microphone so you can listen in as well (currently I hear something like a wailing seagull nearby and the sound of sporadic high-pressure gas venting from the launch area). Occasional running commentary only. On a windy day at the site the sound feed can be very relaxing! Check out LabPadre’s other cameras as well.

Well, SN11 didn’t launch on Monday 29th – but it did launch at 08:00 local time (13:00 BST) on the 30th. An excellent replay of events is here (scroll through to 2 hours 14, and back out when you’ve seen/heard enough!).

It was very foggy at Boca Chica, so ground-based cameras couldn’t see much. However, the NasaSpaceflight feed cut over to SpaceX’s cameras on board. All seemed to be going well, with the starship transitioning to horizontal and controlling its freefall very well. Then came engine re-ignition at an altitude of about 1km just before 08:06…the cameras showing the engines then cut out, and the feed from a ground-based camera showed large pieces of debris raining down on the site, with some impressive clunking noises as they landed. Smaller pieces of debris may have hit some of the cameras in use – this is why it’s a good idea to clear the area when conducting test flights!

The reason for the breakup of the starship remains a mystery at this point, but hopefully the information gained will be of use. The official quote for the flights was that it was an “exciting test”! Nobody at ground level could see what happened fully, so we need to wait for an official word on this.

[Editors comment: Musk also tweeted “At least the crater is in the right place! Apparently, debris found on a bench 5 miles from the launch site – did it explode in mid-air rather than a ground impact?]

NASA SLS

You may recall that NASA managed a partial test (“Green Run”) of its Space Launch System (SLS) at the Stennis test facility in Mississippi, on 19/1/21. This was scheduled to last 8 minutes (the full duration of a launch), but it only lasted just over a minute because of an automated shutdown. On 18/3/21, they tried again – and the engines burned for the full duration. Here’s a video showing the whole event (>1 hour long, but zoom forward to about 47 minutes to pick up the start of the action unless you want the background info).

The amount of water needed to quench the exhaust and deaden the sound of the engines is impressive – the huge clouds of water vapour generated are obvious. The gimballing of the engines during the test is intentional, and is how the rocket is steered in flight. Next, SLS will be refurbished where needed and shipped to NASA’s Kennedy Space Centre in Florida, ready for an actual launch sometime. The plan is for a crewed flight to the Moon in 2024.

Another Fireball

Parts of the UK were treated to a decent fireball on 28/2/21, visible across parts of the South West of England. A chunk of it ended up on someone’s driveway in Gloucestershire and is now known as the Winchcombe Meteorite…

The meteorite is a very rare carbonaceous chondrite, which apparently feels like soft coal. Its composition will inform studies of the formation of the early Solar system, alongside the pristine asteroid samples recovered by the Osiris-Rex and Hyabsa-2 spacecraft. The fireball was caught on several doorbell and other security cameras, and it should be possible to use this information to estimate where the meteor came from.

Then, a sonic boom was heard across the South West of England, Wales and France on 20/3/21. This was not RAF Typhoons on their way to intercept incoming aircraft, but another fireball…

Some folk report a sighting of it during the day, which means that it must have been comparatively large to be that visible. And, if the incoming meteor makes a sonic boom like that, some believe that it’s an indicator that fragments could well have landed. No reports of meteorite findings yet!

Event Horizon Telescope (EHT)

The EHT is a planet-wide network of telescopes operating at mm wavelengths, capable of micro-arcsecond resolution. You may recall the amazing image of the material around the active galaxy M87’s central supermassive black hole, from April 2019. During the observations the telescopes also recorded the polarity of the incoming radiation, and further analysis has been done of this polarisation. The result is striking…..

Polarisation such as this is associated with a powerful magnetic field close in to the black hole. The results can contribute to the understanding of how these black holes “feed”, i.e. draw matter in toward them, which is influenced by the presence of a magnetic field. The creation of the spectacular jets from the centre of active galaxies, like the one from M87, is also associated with magnetism, so the results could help here too. If you want to see the very recent science papers on this, go to here and here The number of people involved in these papers is very impressive.

For a short explainer on the significance of this work, take a look at this video from Prof. Derek Ward-Thompson of the University of Central Lancashire…

Meanwhile on Mars – Ian Bradley

It seems wrong not to report the current goings on with the rovers on Mars as there is plenty of activity. Curiosity continues to do great science and Perseverance is working up to it.

Perseverance after a few short survey trips is gearing up to release the 1.8 kg Ingenuity helicopter. As I write this, the transport cover has been released and the first of many steps in lowering the helicopter to the surface have been taken. The survey identified a ‘flight zone’ and an ‘airfield’, a 10 x 10m square of flat area free from rocks and obstructions.

NASA is billing this as a ‘Wright Brothers’ moment – the first flight on another planet. They even went so far on this linkage as to place on Ingenuity a small piece of the material used to create the Wright brothers’ plane, the Flyer. Don’t worry they didn’t purloin a piece from the actual plane, this was a bit left over from its construction! Apparently, Apollo 11 flew a different piece of material and a splinter of wood from the Wright Flyer to the Moon.

The plan is to position Perseverance on a bluff, Van Zyl Overlook, on the right of the image to video the first flight. This flight will be a sequence of pre-programmed instructions to rise a few meters, hover maybe do a left-right rotation and then return back to the surface lasting only 20 to 30 seconds. It will be an amazing achievement if it is successful. Ingenuity is a flight technology demonstrator and will never go far. It is limited to 90 seconds flight and will probably only travel 300 meters or so. But the Wright Brothers’ flight was only 12 seconds!

Perseverance’s main task is to explore the region, in particularly the remains of an ancient river delta. It has already returned some images of a 10 metre high rock exposure not too far away. Stratification is some exposures is clear.

Meanwhile, over at Gale Crater, Curiosity has taken a nice selfie at the Norton drilling site and Mont Mercou. You can see the drill hole and the surrounding grey dust on the slabs in front of the rover. This image is a mosaic of 60 individual pictures taken with MAHLI camera at the end of Curiosity’s robotic arm on sol 3070 (26 March 2021). Mont Mercou is a stratified butte 7m high and 15m long. This image was assembled by Thomas Appéré using the NASA raw images.

The Blind Philosopher of Kendal – by Eddie Dealtry

John Gough (1757 – 1825)

(and the Shuttle Challenger disaster)

To my complete surprise, a busy pair of tree surgeons enlightened me to the age of a felled tree in Fowling Lane: ‘Probably, planted by the Blind Philosopher’. News to me. On enquiry, the ‘Blind Philosopher’ is news to a number of us.

Arthur Eddington is not our only influential, local physicist, apparently. We can also brag about John Gough (1757 – 1825) ‘The Blind Philosopher’ from ‘Fowl Ing Lane’. Contemp­orary John Dalton (he from Cocker­mouth of Atomic theory fame) described Gough as a ‘prodigy in scientific attainments’. Other contemporaries described him as a self-taught mathematician, physicist, botanist and meteorologist.

An autobiography held by Kendal Archive makes references to his scientific work – dealing with his youth ‘before leaving the world’, continued his by son Thomas (a surgeon of Kendal 1804 – 1880).

Gough was left blind after suffering smallpox at two years old. His mother spent a great deal of time and energy on his ‘Learning when blind’. Early on Gough is demonstrating a prodigious memory for abstract ideas, augmented by a ‘lively idea of appearance’ using the sense of feeling, touch. He could differentiate soils from parts of the garden as well as from different seasons. Thomas records that his father even handled ‘venomous … [and] carnivorous animals with no fear’.

In lines 498-514 of the Prelude – Book Seven of “The Excursion” (1813) – William Words­worth’s writes of Gough:

‘none whose figure did not live/ Upon his touch’

Gough also drew a number of Cambridge students, travel­ling to Kendal for tutoring. Some of their number went on to become ‘wranglers’ and masters of colleges, including the mathematician William Whewell – of the Whewell equation.

John Dalton also visited for tutorials. Notwithstanding, after Dalton’s published his Atomic theory, Gough mounts a vigorous criticism of his (inaccurate) atomic weights.

Gough’s own researches led to a discovery in the thermodynamics of rubber-like materials leading to publication of three experiments, the second and third ‘with a thermometer’! (Reference #2, below). When rubber is under tension, counter-intuitively, it contracts on heating (rather than expanding). The experimental physi­cist James Joule (he of the SI unit of energy) a student of John Dalton (himself a one-time student of Gough) investigated and developed his discovery to become the eponymous Gough–Joule effect.

More than a century after Gough and Joule’s investigations, a low ambient temperature is attributed to the cause of O-ring sealing failures during the tragic launch of Shuttle Challenger .

Previously, the record low temp­erature for a launch was 12°C. At ‑2°C, Engineers refused to sign-off such a low-temperature launch. Neverthe­less, it went ahead. A subsequent con­sensus cites external O-rings failing to seal fuel under pressure as a factor. A ‘primary’ O-ring dropped below the glass transition temperature and the secondary O-ring was not in its seated position – which has been attributed to bending metal. A launch temperature that is far lower than the construction environment, points to the polymer O-rings expanding away from the seal joints for the good folk up Fowling Lane, the Gough–Joule effect.

See also: ‘Memoirs of the Literary and Philosophical Society of Manchester’ are behind a paywall, the society’s Welcome page is here.

New Bright Nova in Cassiopeia – Ian Bradley

In the constellation of Cassiopeia, a new star has been discovered by Yuji Nakamura of Japan. He discovered the object at magnitude 9.6 in four images he took with a 135-mm lens on March 18th where four days earlier nothing was visible brighter than magnitude 13. It has the name V1405Cas if you want to find more details on it from either the AAVSO or the British Astronomy Society.

At the time of writing, March 29th, it is currently at magnitude 7.9, well within the range of a pair of binoculars. It is quite easy to find as it is very close to M52. It is best seen either early evening or before dawn in the northern sky as Cassiopeia dips beneath the Pole Star around midnight so the nova is then quite low, 25°.

There is a useful article in Sky and Telescope on it here.

Star hopping should get you there quite easily by star hopping from Caph, β Cassiopeia magnitude 2.3. A typical binocular field of view is around 6° and for reference, Caph is 5° away from Schedar. Follow the two brightish stars, both magnitude 4.9, and hang a left to the ‘triangle’ of magnitude 6 & 7 stars. The nova is between there and M52, the upper right of the two obvious bright stars below M52 around 10pm at night. The lower star is HIP 115691, magnitude 6.6.

I measured it on March 21st and found it to be magnitude 7.9. It looked reddish in a colour image, albeit one synthesized from narrowband Ha [red] and OIII [blue/green] filter images. My image is over the page together with the AAVSO finder chart with comparison stars if you are interested in trying to determine the nova’ magnitude. Typically, classical novae brighten by 10 – 12 magnitudes over a few days, and then fades by 2 magnitudes over either a few weeks or over 100 days depending on whether it is a ‘fast’ or ‘slow’ type nova. If the weather clears, over the next couple of months, get out and try and repeatedly measure it and plot your own light curve.

So what is a nova? This is a classical nova system consisting of two stars very close together. One is a main sequence or red giant star and the other is a dead star, a white dwarf. A white dwarf is a star that at the end of its life, blew off all its outer layers leaving only the naked core. No fusion is ongoing there and it will steadily cool and dim over time as energy is radiated away.

The two stars are so close together that material from the ‘live’ star streams across the Roche Lobe onto the surface of the white dwarf, accretion. Over time, sufficient material builds up to satisfy the temperature and density criteria for fusion to occur, and some of the surface material ‘ignites’ blasting off the majority of the accumulated material. It is this hot expanding envelope that we see. As a large fraction will be hydrogen, I’m not surprised that I detected lots of hydrogen in my colour image.

Recent Photos – Ian Bradley

The California Nebula in Pegasus. This large nebula is excited by the star on the right – Menkib, Xi Persei, a very hot and bright type O7 star. I had difficulties with haze and low altitude for the lower half of the two-panel mosaic. A project for next year…

Two-panel mosaic imaged from Kendal over the nights of February 28^th and March 2^nd using a Skywatcher 10″ Newtonian, and a QHY163m mono camera with Hα and OIII filters. Hα mapped to red and OIII to both green and blue. Total exposure time over 8 hours.

Who can resist the Horsehead and Flame nebulae. Taken March 1^st with a very strong Moon using using a Skywatcher 10″ Newtonian, and a QHY163m mono camera with narrowband Hα and OIII filters with Hα mapped to red and OIII to both green and blue.

Supernova SN2021gmj in NGC3310 in Ursa Major. The star was discovered on 20 March 2021 at magnitude 16. My photograph was taken on March 21^st @ 20:45 when I estimated it [with difficulty] to be 14.5. I was probably generous due to contamination from the spiral arm in my estimation as others see it as just over 15.