Comet C/2025 A6 Lemmon’s show is coming to an end, at least for observers in the northern hemisphere.
Having shone bright enough to be clearly visible to the naked eye in the evening sky during the last week of October 2025, when it gracefully approached and then passed above the bright star Arcturus, the comet is now sinking lower and lower in the west each evening.
Soon it will exit the northern sky and become more clearly visible from the southern hemisphere, but it is already well past its best and will now fade quickly as it heads away from the Sun, back into the deep dark, not to return again for over a thousand years…
Don't believe the hype?
As is sadly the way these days, Comet Lemmon was hyped up to a huge degree on social media when it moved into the evening sky, but it never 'lit up the night sky' as many of those posts claimed.
It wasn’t – and was never going to be – a Great Comet like Hale-Bopp or Hyakutake, but it was a very pretty sight through binoculars and telescopes, and was, as predicted, visible to the naked eye from dark locations at its best.
When it is gone, comet observers will be left with very fond memories of this icy visitor from the cold, dark depths of the Solar System.
Observing Comet Lemmon
But we had to work for those memories, didn’t we?
When the comet was at its best in the morning sky at the end of September, and once it had moved up into the evening sky, clear views of it were very hard to get because a pattern of foul weather filled almost the whole of the UK’s skies with thick cloud that simply refused to budge.
After several frustrating weeks of trying to see and image Comet Lemmon from Kendal, Cumbria, UK, I’ll admit I was quite desperate to get a good look at it from Kielder Campsite in Northumberland we went to up there recently.
But the cloud seemed to follow us there, and for the first four days the comet stayed hidden from view.
To my huge relief, the clouds eventually parted, revealing Comet Lemmon to the lower left of the Big Dipper’s curved handle, en route to its rendezvous with Arcturus.
I was FINALLY able to enjoy many good observing sessions of the comet, with my naked eye, through binoculars, and also through my telescope.
I took lots of lovely images with my Seestar too, which turned out better than I’d expected – and dared hope – they would.
Tracking Comet Lemmon
I also took lots of photos of the comet using my 'veteran' astrophotography rig: an original iOptron Sky Tracker and DSLR.
If you’re not familiar with them, the original Sky Trackers were basically big, white metal bricks, almost as heavy as a bowling ball.
They were so basic – essentially just clockwork drives – that they’re not made anymore. Star tracking technology has moved on and they’re now museum pieces, replaced by much more advanced and much more complicated models.
My Star Tracker is in its twilight years now. Its battery compartment cover is held on with fraying duct tape.
Its once snow-white paint is now faded and chipped in places; its elevation adjustment knob sticks and creaks like an arthritic knee; the ticking of its motor, once as soft as the ticking of a Swiss watch, is now starting to sound wheezy and strained.
But it refuses to die, and as we headed up to Kielder I was really, really hoping it would give me some good images of Comet Lemmon before it was aligned on Polaris for the last time.
Once the cloud cleared, I set up my iOptron and started taking photos.
They looked very promising on the back of the camera (they always do!), but I was unable to look at them properly or process them until we got home, thanks to my new laptop dying.
Frustrating? Just a bit… Now, a week after returning home, I’ve finally managed to process those images.
And wow… what a comet Lemmon was photographically.
To my amazement, my DSLR images showed the tail stretching away from the comet’s head for ten degrees or more.
I’d seen this on images taken by astrophotographers using state-of-the-art kit and advanced processing techniques, from locations with skies as dark as the Moon’s, so I was amazed and delighted to see them on mine.
The detail in the tail was just remarkable, and the blue gas tail and yellow-white hues of the dust tail are really obvious too.
One last chance...
Comet Lemmon is now sinking into the west after dark, and will soon be gone. Last night I tried one more time to image it, using my Seestar.
The sky here in Kendal is wrecked by light pollution, so I didn’t expect much success, and I only had a twenty-minute or so window to try and get the comet during a gap in the cloud, but I caught it just before it dropped behind the houses.
It has faded a lot since I saw it under Kielder’s dark sky, and its tail has shrunk too, but it is still a beautiful comet photographically, and southern hemisphere observers will still get some great views and images before it fades away completely.
So, farewell Comet Lemmon and thank you.
Maybe you didn’t 'light up the sky', but you were still beautiful, and we’ll miss you.
Share your memories and images of Comet Lemmon with us by emailing contactus@skyatnightmagazine.com
