A dying SWAN..?

Late posting this due to work pressures, but I finally managed to image Comet SWAN F8 late on Wednesday night / early on Thursday morning. I can’t say I saw it because I didn’t; it was far too small, and far too faint, and hanging far too low in far too bright a twilight sky for that, and no amount of scanning with my binoculars pulled it out of the sky. In fact, although I began photographing the comet’s area at around 11pm it wasn’t until 45 minutes later that it began to actually show up on the images.

The next day when I was finally awake enough to review those images the comet was only barely there, and it took a lot of stacking and processing to bring it out of the pale sky.

But I got it, and here’s Comet SWAN F8 as photographed around midnight on May 20th, through a 135mm lens on a Canon 700D DSLR tracking the sky on an iOptron tracker. These are stacks of multiple images which were then processed to bring out the comet more clearly.

Full 135mm frame. Comet SWAN is the small smudge in the centre.

A crop from the previous image, showing the comet more clearly.

So, I think it’s now clear that we can forget any last, lingering hopes that Comet SWAN is going to reach naked eye brightness. Yes, it’s going to slowly climb higher in a darker sky over the next week or so, but I can’t see that making much difference. The comet is a pale shadow of the one that delighted southern hemisphere observers earlier this year, little more than a roughly cone-shaped smudge on tracked, stacked, long exposure photos taken with a long lens. I’ll be amazed, actually, if it doesn’t fade from view altogether soon. But you should try and find it if your sky and weather allows, just so you can say you did in years to come when many astronomers are looking back at how two comets in a row, ATLAS and then SWAN, failed to live up to their potential.

But all is not lost. There is a comet in the northern sky that is definitely worth looking at and is easier to see and photograph than SWAN too. C/2017 T2 (PANSTARRS) is currently up near the Big Dipper, passing a very famous pair of deep sky objects – the galaxies M81 and M82. I imaged it after imaging SWAN the other night, and was pleasantly surprised by how bright and easy to photograph it was. The images below were taken with the same equipment as the ones of Comet SWAN above. The galaxies are bottom left, the comet is top right.


So where is it? Here are some charts…

So, farewell Comet SWAN? I think so, though it would be great to be proved wrong. But let’s end this update on a positive note! There is another comet on the way that might… might… put on a nice show in the summer. I know, I know, we said the same thing about ATLAS and SWAN, but maybe we’ll be lucky this time…

As you can see from this chart, during July Comet C/2020 F3 (NEOWISE) is going to arc up into the northern sky and pass beneath the stars of the Big Dipper.

Looking ahead, how bright will it be? We don’t know. We can’t know. There are magnitude estimates flying about but obviously after what happened with ATLAS and SWAN it’s wise to take all those with a huge pinch of salt. Let’s just wait and see what happens. IF it reaches a decent brightness it might offer us some very pleasing views…

Do NOT take that graphic as a prediction of how F3 will look. I’m just showing where it will be, not predicting it will have a long tail like that! Likewise…

And that’s where we are. Give Comet SWAN a go if you haven’t already, but be prepared to be thoroughly underwhelmed, and then track down T2 up near the Big Dipper. Good luck!

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