Balmy nights of brilliant sights
Astronomer Will Gater picks out the celestial targets that will keep both observers and imagers enchanted on clear, June nights
When I was getting into astronomy it was always said that, as summer arrives, the lighter nights make observing sessions rather pointless What I eventually learnt is that while chasing the dimmest faint fuzzies at the eyepiece might be out of the question in June, the warm evenings can still be a time when treasured celestial memories are made. There’s certainly no reason to leave the telescope or binoculars gathering dust this month, with some fine star clusters, noctilucent clouds, planetary alignments and more to be seen. In this article we’ve picked out a selection of phenomena that will hopefully provide some satisfying observing and imaging challenges during the nights of June. And while our list is tailored slightly more to the interests of an intermediate-level astronomer with photographic kit to hand, there are some great beginner targets scattered among them.
The Beehive Cluster
We begin our journey around June’s night skies with a goodbye of sorts, looking at a spring target that’s sinking into the west now that summer’s here. On the night of 1 June you’ll find the beautiful Beehive Cluster, M44, dropping low on the west-northwest horizon as midnight approaches. It’s the perfect observing target for 10×50 binoculars, or similar, which will show the numerous glittering stars of the open cluster scattered around a patch of sky that’s roughly a degree across. A few nights later, on 4 June, the crescent Moon lies about 6.5° from the Beehive Cluster. With earthshine – when light scattered off Earth lights up the Moon’s night side – showing up at this lunar phase, the arrangement could make for some striking nightscape-style astrophotography compositions.
ASTROPHOTO HIGHLIGHT
Asteroid Psyche
Our first astrophoto highlight is a target that’s ideal if your deep-sky imaging rig is getting a little less use now the lighter evenings are upon us. Asteroid 16 Psyche orbits within the main asteroid belt and it is going to be visited by a NASA spacecraft that’s due to launch in August. The mission’s namesake will be positioned in the constellation of Leo, the Lion, in June and, at around 12th magnitude, should be in range of a modest telescope and DSLR or CCD camera combo. Around 1 and 2 June the asteroid is sitting not too far from some of the brighter galaxies in Leo. With a bit of clever framing, using a wide-field setup and some stacked long-ish exposures, it may be possible to capture the point of light that is Psyche in the same field of view as the likes of M95 and M96.
Coma Star Cluster
The Coma Star Cluster is in the L-shaped constellation of Coma Berenices (Berenice’s Hair) and it lies about halfway between Denebola (Beta (β) Leonis) and Cor Caroli (Alpha (α) Canum Venaticorum). The cluster can be tricky to see from lightpolluted locations, but it can be viewed with the naked-eye from a dark suburban spot. It looks superb in a pair of 10×50 binoculars and is dominated by 4th-, 5thand 6th-magnitude stars. The best time to view the cluster will be in the days leading up to 5 June, after which the Moon will interfere. Find it about 30–35° above due west around 01:30 BST (00:30 UT).
Messier 53
We don’t have to go far to find the next target. It’s a telescopic object suited to a larger scope of 8-inches (200mm) or more: the globular cluster M53. It also sits in Coma Berenices, about 14° away from the Coma Star Cluster. If you intend to star hop to M53, first identify the extended ‘L’ shape of Coma Berenices (see the all-sky chart in the ‘Sky Guide’ if you need a refresher). Then direct your finderscope towards the 4th-magnitude star Alpha (α) Comae Berenices at the other end of the ‘L’ from the Coma Star Cluster. From here head northeast by about a degree and M53 should fit nicely in the field of view of an eyepiece giving around 70x to 80x magnification.
Scorpius on the horizon
If you’re observing or imaging from a location with a clear southern horizon, look towards the constellation of Scorpius, the Scorpion. This region of the sky is often hidden by the skylines of towns and cities, so it’s a good one to look out for if you’re heading away from home. From the UK, the constellation will be spanning the meridian around midnight in late June, when the Moon is out of the way. Its low altitude makes it suitable for wide-field nightscapes over distant horizons, with the bright stars comprising the pincers and head of the Scorpion balanced against rich Milky Way star fields nearby.
ASTROPHOTO HIGHLIGHT
The Prancing Horse Nebula
Move (very slightly) to the east from Scorpius and you can turn your attention towards the bright star fields of the Milky Way that lie next door in Ophiuchus, the Serpent-Bearer. This region is close to the core of the Milky Way and the dense swathes of stars here are crossed by numerous dark nebulae, interstellar clouds of gas and dust within the Galaxy. One, the so-called Prancing Horse Nebula, is an especially striking astrophotography target, suited to both nightscape and deep wide-field imaging. In June, with little real darkness around, you might like to try the former. The nebula is easy to find as it’s mostly contained within a triangle made by the very bright stars Antares (Alpha (α) Scorpii), Lambda (λ) Sagittarii and Eta (η) Ophiuchi.
Occultation of Theta Virginis by the Moon
This month we have a chance to see the lunar disc hide a relatively bright star during an event known as an ‘occultation’. Though professional astronomers often use occultations by Solar System objects to refine their understanding of the orbits and shapes of distant bodies, this event is more of an interesting telescopic spectacle than anything else. At around 02:00 BST (01:00 UT) on 10 June, the star Theta (θ) Virginis will be covered by the dark southwest limb of the 75%-illuminated gibbous Moon from the UK. Use planetarium software to confirm your exact local circumstances and aim to be observing around five minutes beforehand so you can catch sight of the star before it suddenly disappears from view.
ASTROPHOTO HIGHLIGHT
C/2017 K2 PanSTARRS near IC 4665
The comet C/2017 K2 PanSTARRS was discovered by the PanSTARRS project in 2017. It’s now heading into the inner Solar System on a hyperbolic orbit. This month the comet is relatively high in the UK sky and will be passing through the constellation of Ophiuchus. At the start of June it’s about halfway between the stars Zeta (ζ) Aquilae and Beta (β) Ophiuchi, and on the nights of 19/20 and 20/21 June it will pass less than a degree from the open star cluster IC 4665, in Ophiuchus. This should provide a great opportunity for wide-field imaging with either a long camera lens or wide-field telescope. The Moon rises at about 01:25 BST (00:25 UT) on the 19/20 June, so capture your exposures before its light washes out the sky. The next night the Moon is out of the way until about 01:40 BST (00:40 UT), when it pops above the horizon.
The Scutum Star Cloud
Look due south around 02:00 BST (01:00 UT) this month and, at least from the southern parts of the UK, you’ll be able to glimpse the Milky Way rising from the horizon. Low down in the Milky Way sit the bright stars that make up the ‘Teapot’ asterism in Sagittarius, the Archer, and above them lies the less prominent constellation of Scutum, the Shield – its most striking feature being the famous star ‘cloud’, which dominates its northern half. The Cloud is really a bright patch of Milky Way star fields that stands out from the band of the Galaxy surrounding it. It’s visible from dark suburban locations if the sky transparency is good, and it makes a wonderful sight in binoculars if you’re far enough away from light pollution.
Andromeda’s satellite galaxies
Many of us have marvelled at the Andromeda Galaxy, but have you ever looked for its two most prominent satellite galaxies? M32 and M110 appear close to the centre of Andromeda and are good targets for a medium-or large-aperture telescope. You’ll find the Andromeda Galaxy sitting about 30° above the northeast horizon around 01:30 BST (00:30 UT) towards the end of June. A nice way to view M32 and M110 is to select an eyepiece that produces a field of view about 2° across, as this allows both targets to be seen at the same time, with Andromeda’s disc cutting in between.
ASTROPHOTO HIGHLIGHT
The Cat ’s Eye Nebula
What’s the simplest astrophotography setup that you can image a planetary nebula with? How about a DSLR camera and a medium focal-length lens on a static tripod? If that sounds intriguing, here’s an imaging challenge to try this month. The Cat’s Eye Nebula is a planetary nebula around 3,000 lightyears away towards the constellation of Draco, the Dragon. It’s just about bright enough that, if you have reasonably dark skies, you can pick up signs of it with the kit described above. For our image (below) we used a 50mm lens. Now, you’re not going to capture any detail in the nebula at that focal length, but you will be able to pick it out as a tiny greenish point of light. To be in with the best chance of detecting the nebula, try a star trail-style shot, in which you take multiple long-ish exposures – 30-seconds at least – and then stack them together with your preferred star trail-creation software. What you’ll find is that the Cat’s Eye Nebula stands out conspicuously from the stars as a greenish-blue arc.
Noctilucent clouds
As early June comes around we should start seeing noctilucent clouds (NLCs). These clouds of ice crystals in the mesosphere make wonderful targets for observing and imaging. Indeed, their always-different, always-changing shapes – as viewed against vibrant twilight skies – are particularly suited to timelapse astrophotography. In the evening, look for them low on the northern horizon about an hour after the Sun has set.
You’re looking for thin wisps and tendrils of whitish-blue light, sometimes in snaking river-like forms, other times with wave patterns embedded in bright curtains of light. Binoculars are an effective way to visually monitor the motions within a display over the course of a minute or so.
For more information and tips about spotting noctilucent cloud displays, see the ‘Sky Guide’
Predawn planets
At around 03:30 BST (02:30 UT), from 24 June to the end of the month, there will be a striking array of planets aligned across the sky. If you have a clear view, such as a sea horizon, to the eastnortheast you may be able to see Venus sitting around 2° above the horizon. The display will stretch westwards from there, along the ecliptic, with Mars, Jupiter and Saturn visible too. A camera may be able to pick up the speck of Neptune as well. From 24 to 26 June, a thinning crescent Moon will be visible between Mars and Venus, which adds another captivating element to the show.
ASTROPHOTO HIGHLIGHT
Cloud trails around the Moon
The chances are that at some point this month clouds will interfere with our observing sessions, but that shouldn’t stop us from trying out some astrophotography. One way I like to use passing clouds is in long-ish exposure nightscapes of the Moon. You can use an exposure of several seconds to allow the clouds to trail as they drift by the lunar disc. The challenge is to find an exposure and ISO setting (and the right gap in the clouds) that gives you detail on the Moon but also in the textures of the clouds. This requires some trial and error as you try to balance the exposure and the amount of blurring, which will depend on the exposure length and how fast the clouds are moving.
Will Gater is an astronomy journalist and science presenter.
His latest book, The Mysteries of the Universe, is published by DK.