What’s in the sky this month – Ian Bradley EAS
Summer is most definitely here, darkness-wise. After May 9th, it never gets fully dark until August 3rd. So make the most of the remaining darkness whilst you can. Deep sky observing will soon get difficult and during June almost impossible. Therefore I’ll try and indicate a few things to look for mainly during May and July.
Ian Morrison’s [Jodrell Bank] monthly notes
Noctilucent Clouds – NLC
We may see NLC’s from around late May to early August during the darkest part of a summer’s night. They will occupy the northern horizon, along the twilight arch, extending to an altitude of 10 – 15 degrees. They form at very high altitudes – around 82 km above sea level – and are, thus, a quite separate phenomenon from normal weather or tropospheric cloud.
The bright star Capella, in Auriga, on the northern horizon is a good marker. The clouds, if they form, tend to appear sometime between 2300 BST and 0200 BST. Unlike aurora, there is no warning [or app] indicating whether they will form any particular night – you just have to look as they are completely unpredictable. Sometimes we get stunning displays, other times nothing all season. Normal clouds always look dark whereas NLC’s appear as thin ghostly streaks of “cloud”, often a pearly-blue colour.
ISS visible passes
There are so many ISS passes visible that it is impractical to list them all here. Typically there are two per night [with some in the early morning] throughout May and also July, but none listed in June. If you want to see the ISS, I suggest you look at Heavens Above website https://www.heavens-above.com/ and set your location. Heavens Above will also tell you about other satellites, including the dreaded Starlink ones…
Possibly, one of the most reliable things you can see this time of year! Some of us tend to ignore it [including me sometimes] but it can be a gorgeous object to view with binoculars or a telescope. Look particularly close to the terminator between the illuminated portion and the unlit portion as that is where the most interesting detail can be seen. In good conditions, shallow ridges of lava flows can be seen on the maria when they are under low angle illumination.
On June 5th, the Moon rises [21:28 BST] during a penumbral lunar eclipse. As the maximum eclipse is at 20:25 BST with the eclipse ending at 22:04 BST, this subtle darkening of the southern edge of the Moon is likely to be very difficult to see. There is an even worse one July 5th – forget it!
Venus has been unmissable at sunset. It shows a lovely narrow crescent phase in a small telescope: 25% at the beginning of May when it is about 64° from the Sun. As the month progresses, the phase will ‘narrow’ as the planet approached the line form the Earth to the Sun. By the end of May, it will be only 10° from the Sun and a phase of 2 degrees but similar brightness to now, and probably very difficult to see – a challenge for you! If you do look, I’d wait until the Sun has set, around 21:30. Venus will be only 6° above the NW horizon. Take care: never look at or near the Sun with your naked eye or especially binoculars or telescope!
In the morning sky, we still have Mars, Jupiter and Saturn about 10 degrees above the horizon in the south and getting quite difficult in the twilight. Jupiter and Saturn will be around opposition [opposite the Sun in the sky and therefore at their best] during mid-July but they are still very low being around 10°—15 ° above the horizon, so conditions won’t be great.
Mercury, currently very close to the Sun, will soon pass behind the Sun and reappear as an evening sky, reaching its maximum eastern elongation [angular distance from the Sun) of 23°on June 4th. As the Sun sets at 21:30 and Mercury about 23:30, you should be able to see the planet quite well despite the twilight. Take a look a couple of weeks either side… On July 22nd, it has its greatest western elongation [20°] and be seen in the morning sky.
There are four binocular comets about at the moment.
|2019 Y1 (ATLAS)||8||Fading||80N to 25N||Evening|
|2020 F8 (SWAN)||8||Brightening||0N to 85S||Morning|
|2017 T2 (panSTARS)||9||Steady||70N to 5N||All Night|
|2019 Y4 (ATLAS)||9.5||Brightening||80N to 5S||All Night|
Three of these comets are in the same region of the northern sky. Capella, in Auriga, and Castor and Pollux, in Gemini, are helpful signposts.
Comet C/2020 F8 (Swan)
This one could be interesting although it is only currently visible from the southern hemisphere but it does have a bright tail. The comet is expected to reach naked-eye visibility by mid-May low in the eastern dawn skies. The star chart shows how the sky will look from Kendal at 4am on May 15th. The horizon will depend on your observing time and date so orientate yourself using Capella and Mirfak.
Maybe coming soon – Comet C/2019 U6 (Lemmon). It goes through perihelion (closest approach to the Sun) on June 18 and then it should appear low in our northern sky… its magnitude will be anyone’s guess, or even if it will survive!
Whilst on the subject of comets… my quote last month “Comets are like cats. They have tails and they do whatever they want” has proved to be rather prophetic. Comet C/2019 Y4 (ATLAS) was being hyped by some newspapers as ‘the comet of the century, as big as the Moon’…the usual ignorant trash. Well, the prediction [with all the usual caveats] that this was likely to be a naked eye comet looks to be wrong. Late March, the comet stopped brightening and on April 6th, one observer reported that the nucleus seemed elongated. Over the next few nights, it became clear that the nucleus, the central icy body, the source of the material that forms the most obvious part of a comet, the coma, and the tail had disintegrated. Whilst there is currently at least one reasonable fragment left, it is unlikely to be as bright, or even naked-eye visible, in mid-May.
Comet C/2019 Y4
March 25th 2020
April 14th 2020
The comet plus an inserted x3 enlargement. Only two of the 4 fragments show in this photograph. The lead fragment was actually two.
April 21st 2020
May 4, 5 – Eta Aquarids Meteor Shower- can produce up to 30 meteors per hour at its peak. It is produced by dust particles left behind by comet Halley. The shower runs annually from April 19 to May 28. It peaks this year on the night of 4th and morning of the 5th but the nearly full moon will be a problem this year blocking out all but the brightest meteors. You may still be able to catch a few from a dark location after midnight. Meteors will radiate from the constellation Aquarius but can appear anywhere in the sky.
July 28, 29 – Delta Aquarids Meteor Shower at can produce up to 20 meteors per hour at its peak. It is produced by debris left behind by comets Marsden and Kracht. The shower runs annually from July 12 to August 23. Again, the moon will block many of the fainter meteors this year.
Looking further ahead, August 11, 12 – Perseids Meteor Shower. The shower runs annually from July 17 to August 24. Usually one of the better meteor showers to observe, producing up to 60 meteors per hour at its peak. It is produced by comet Swift-Tuttle. The shower ends to have a large number of bright meteors. Again, we have a moon to contend with, but the Perseids are so bright and numerous that it could still be a good show.
The charts are for mid-May. Each month the sky rotates westward 30° so you can use these charts for June and July but remember to allow for this rotation. New objects will appear in the east, and you lose some in the west.
Looking south, mid-month (May 15th) at 23:00 BST
Dominated by the constellation Virgo and Bootes with Leo still prominent in the SW. Galaxies are getting difficult due to the lack of darkness but there are still star clusters well worth a look. M3, a globular cluster which is nice in binoculars. Other globular clusters M5 and M53 are worth seeking out. Melotte 111, the Coma Star Cluster in Coma Berenices is a small but nearby star cluster in our galaxy, containing about 40 brighter stars (magnitude 5 to 10). The open cluster is roughly twice as distant as the Hyades and covers an area of more than 7.5 degrees on the sky. It fits nicely into the field of view of a pair of binoculars. The brighter stars of the cluster make out a distinctive “V” shape.
Looking west, mid-month (May 25th) at 23:00 BST
Still dominated by Venus. The constellation of Orion is now gone but Gemini is prominent and Auriga further north. There are a trio of messier objects, M36, M37 and M38, in Auriga which are fine binocular targets, with M35 further south in Gemini. For other interesting objects, look at last month’s newsletter.
Looking east, [below] mid-month (May 15th) at 23:00 BST
The three most prominent stars form the asterism, The Summer Triangle: Vega, Deneb and Altair. The Milky Way and its luxurious star fields runs right through Cygnus and Aquilla… so well worth a look. But globular clusters are really it here… M5, M10, M12, M13, M92 several of which are easy in binoculars. In addition, there are two bright telescopic planetary nebulae to look for – the magnificent, if small, M57 The Ring Nebula and the larger Dumbbell Nebula M27. M52 in Cassiopeia is also a nice binocular object.
Looking north, [below] mid-month (May 15th) at 23:00 BST
It will be rather bright in this direction throughout the summer as the Sun isn’t that far below the horizon. The chart will also help you locate the comets.
Looking up, [below] mid-month (May 15th) at 23:00 BST
Here Ursa Major still dominates with its familiar plough or saucepan asterism. It’s an area rich in telescopic galaxies, some just visible in binoculars. M81 and M82 are a spectacular pairing. M101, the Pinwheel Galaxy and M51, actually in Canes Venatici, are stunning photographic objects if you can spend time on them. The nearby Owl Nebula M97 is also interesting – a visually circular planetary nebula with two darker spots resembling the head and eyes of an owl.