The North bids Farewell to Comet Leonard…

Tracked and stacked image of Comet A1 Leonard imaged by S Atkinson on Dec 9th 2021

So, proving the doom-mongers wrong, Comet C/2021 A1 Leonard did not fall apart. Since our last update it has continued to brighten, develop a tail and fall towards and then past the bright star Arcturus. At the start of December it was visible for a period of many hours before sunset for observers in mid-northern latitudes. Now, as we approach mid-month, the comet is so far down its morning “track” that it is only visible for a couple of hours before sunrise, and is becoming harder to see. If you have a low NW horizon where you live, uncluttered by trees or buildings, you might be able to see it after sunset, but it will be very challenging.

Comet A1 Leonard just after rising on the morning of Dec 9th 2021. Image: S Atkinson

Visually, Comet Leonard remains pretty, but small. This image – a composite of three different images taken using the same camera, lens, settings and exposure – shows how it compares in size to the famous Pleiades star cluster and Orion Nebula (note: the comet is NOT in this position in the sky, it is nowhere near these objects, which aren’t this close to each other in the sky too, this is purely a composite image)…

Composite image – S Atkinson

It has a glowing green head, and a tail that can be seen through binoculars and telescopes and can be followed for up to ten degrees in long exposure photos. At magnitude 5 or so it is theoretically bright enough to be seen with the naked eye, and a few experienced observers have seen it without any optical aid, but due to its low surface brightness, short tail length and low altitude in the sky the only people who will see it with their naked eye are those who know exactly where to look and what they’re looking for – an out-of-focus star with a hint of a tail behind it. Unlike Comet Neowise, which delighted us a couple of years ago, this is not a comet you will be able to see just by looking in the right direction. Leonard is small, and faint, and has not (yet?) developed a long tail to make it stand out in the sky.

Stack of 40 images of Comet A1 Leonard taken on the morning of December 10th 2021, showing the comet’s tail fanning out. Image – S Atkinson

Comet A1 Leonard will soon drop out of sight for northern hemisphere observers, then it will be the turn of our friends down south to see it. The latest photos suggest that the comet’s tail is now starting to broaden and fan out, so it may yet put on a good show in the southern sky, sporting a brighter, curved tail in a week or so, but we’ll have to just wait and see.

Is it still worth looking for this comet from the northern hemisphere? Of course! Comets this bright appear so rarely that you should get out there and look for them any chance you get! But if you don’t manage to see it don’t worry, 2022 is bound to bring new comets to our skies, and we’ll let you know where to look for them.

And, who knows, maybe 2022 will be the year a truly Great Comet, one to put Hale-Bopp to shame, appears…