Comet C/2023 A3 (Tsuchinshan-ATLAS)

[Ross Wilkinson]

This is the comet which we spoke about at our meeting last Tuesday.

The following day, David got this picture from Norfolk:

but that night we had torrential rain here in Bolton.

I had to wait for an opportunity to catch it from home - Saturday looked promising, but the clouds started rolling in at twilight. I'd taken a shot around 7pm of the bright sky just to test the camera, but couldn't see anything on its rear display. However when I looked at the image on a PC screen, the following morning I found that I had caught the comet after all:

That's just a single shot with my Sony NEX5 and a Pentax 50mm lens and the bright glow in the bottom right isn't from the setting Sun: it''s a streetlamp just across the road!

A couple of minutes later, the clouds came over, so I didn't manage to get any more data to stack.

[Ross Wilkinson]

This frame from 7:48pm shows the position of the comet relative to that streetlamp:

[Ross Wilkinson]

Monday (21st) was a much clearer night, so I'd managed to integrate over 700 seconds of data by 7:30pm:

And I even managed to see it in binoculars, making it my 23rd visual comet detecton (plus another 102 with CCD only).

[Ross Wilkinson]

Having filtered out some of the subs which were too bright, or marred by aircraft & satellite trails, I was left with a stack of 50x 9-sec.

Then after some more fiddling with Siril and GIMP, this is what I got:

[Ross Wilkinson]

It wasn't until a month later that I got another chance to catch this comet, by which time it had dimmed to 8th magnitude.

This time I used my old Starlight Xpress Hx916 mono CCD camera fitted with a Pentax 200mm lens, on a Celestron LCM (tracking Alt-Az mount), set up outside the kitchen door again:

This is a stack of 56x 20-sec, processed in IRIS. The stacking accounts for the comet's movement, so the stars are slightly trailed.