For the past few months northern hemisphere comet observers have been enjoying observing and photographing Comet 12P Pons-Brooks. At its best, this famously outburst-prone comet – rather oddly and inaccurately dubbed “The Devil Comet” or “The Devil Horned Comet” in the media – was just about visible to the naked eye to observers blessed with both very good eyesight and very dark skies not spoiled by light pollution, but for the rest of us who don’t have the eagle eyes of the Six Million Dollar Man or desert-dark skies it was a very pleasing binocular object and very interesting photographically too. That comet has now dropped out of the northern sky and has moved into the southern sky, where it is still being observed and photographed by more southerly comet watchers.
In the north many comet watchers are turning their attention to other comets. Moving through the frothy star clouds of central Cygnus, 8th magnitude Comet C/2021 S3 PANSTARRS has a very interesting whip-like tail which is quite striking on photos taken through telescopes, but another, much fainter comet is the one most comet collectors are now looking for: Comet C/2023 A3 (Tsuchinshan-ATLAS), aka “The one that might be bright in the autumn”.
At the moment this comet is a late evening object for northern observers, drifting slowly through the zodiacal constellation of Virgo, tracking westwards above the constellation’s brightest star, first magnitude Spica as it passes just beneath 3rd magnitude Heze. The comet is still very dim, shining – if that’s the right word – at around tenth magnitude, but it is easily found in small telescopes and can now be imaged with just an entry-level DSLR camera and long lens mounted on a star tracker to allow it to take time exposures.
Over the past few nights I’ve been imaging this comet from Kendal, in the Lake District, taking advantage of a run of unusually clear nights. Using a Canon 700D DSLR, a 300mm lens and a motorised tracking mount I’ve been able to capture the comet quite easily, even with moonlight and light pollution brightening the sky. It very clearly a fuzzy, non-stellar object in my photos, and when the images are stacked together and processed the comet even appears slightly elongated, hinting at the presence of the short tail evident on images being taken through large telescopes using much more sophisticated cameras – a promising sign, considering the comet is still so far away, halfway between Mars and Jupiter in fact.
Through until the end of May the comet will continue to move through Virgo…
After leaving Virgo the comet will cross the border into the deep south of the neighbouring constellation of Leo in mid-June. By then it will best be seen after midnight, low in the south-west, but will probably still be much too faint to see with the naked eye.
Comet A3 is faint and small now, and will be for some time yet, but everyone is wondering what this icy visitor will do as it rounds the Sun in September, because after A3 was discovered there were all sorts of amazing predictions flying around. It was going to be a Great Comet, some said, perhaps the brightest since Hale-Bopp! It was going to be a striking sight in the evening sky in October, maybe even visible in broad daylight when it was at its brightest! All hype and speculation, of course; although the comet certainly has potential to be brighter than the comets we’ve seen over the past couple of years, there’s absolutely no guarantee it will be an impressive sight in our sky later in the year, no matter what you read online. We’ll just have to wait and see. In the meantime, even though Comet A3 is just a faint, fuzzy star at the moment, it’s definitely still worth keeping an eye on; the more observations we can make of the comet the more we will be able to predict what it will do in the future. Besides, if the comet does become bright in the autumn it’ll be fun to look back on how much less impressive it looked now, and you’ll be able to say “I knew it when…”
So, if your sky is clear any time soon get out there, find Virgo, and look for Comet C/2023 A3 (Tsuchinshan-ATLAS) close to it with your camera or telescope. It might not look like much now, but later in the year who knows? Just remember…
Stuart Atkinson
Top image: crop from a processed stack of 30x 30s ISO 800 images taken using a Canon 700D DSLR/300mm lens/iOptron Sky Tracker, from Kendal, Cumbria, late evening Thursday April 25th 2024 TAken by S Atkinson