Comet C/2021 S3 (PANSTARRS) passing through Cygnus

[Fegato]

A clear night last Saturday - from dusk till dawn, a first this year for me, albeit dusk and dawn a bit closer together than they have been!

I've got limitations to low altitude targets to the north, but can just about get down to 30 degrees in the NE, and can get at the northern part of Cygnus now. I spotted this comet passing through, so thought I'd have a go at it against a busy background. This is only my second comet attempt, and the other one was over a year ago and simpler (just a dark background). So... processing this was a pita, I had to CometAlign the comet and essentially remove all the background, star align removing the comet, and then get the two back together again. Took a lot of fiddling around to get things to work as I wanted, and I have to own up to some CloneStamp usage (just for mask creation and some background correcting - I didn't "draw" the comet, I promise!).  

The comet isn't spectacular, and I couldn't find any colour (was hoping for a nice bright green head!), but it adds something different to this rather red scene. Mostly LBN and LDN categorised nebulae here, but Simeis 57 (aka Propeller Nebula) is down at bottom left.

RASA 11 v2 on CEM120, ASI2400MC Pro, 91 x 30s

Edited May 8 by Fegato
added acquisition details

[happy-kat]

That does look a very fiddly comet process but worth it, great result

[WolfieGlos]

That's a superb result, really nice image!

I'd dread to think of the processing involved to get the comet into that background.

[Sunshine]

It’s beautiful!

[Fegato]

7 hours ago, WolfieGlos said:

That's a superb result, really nice image!

I'd dread to think of the processing involved to get the comet into that background.

Thanks!

I guess the final solution wasn't too bad - it just took a while to get to it! (and I really should write it down, bound to forget).  Once I worked out how to use it properly, the CometAlign process in Pixinsight did a very good job at producing an image with no comet in it (just a tiny bit of a background hole next to the comet head to correct).  But the aligned comet image was a right mess, even after removing all the stars from every frame before running it. I literally painted a mask around the comet master (heavily convoluted)  and removed everything except the comet, set the empty background to median level, and then added it to the comet-less image. 

Have to say that the ability to quickly and efficiently remove stars at various points to check or correct the odd blemish was critical. Not sure how I'd have achieved anything much without the ability to do that.

[WolfieGlos]

2 hours ago, Fegato said:

Thanks!

I guess the final solution wasn't too bad - it just took a while to get to it! (and I really should write it down, bound to forget).  Once I worked out how to use it properly, the CometAlign process in Pixinsight did a very good job at producing an image with no comet in it (just a tiny bit of a background hole next to the comet head to correct).  But the aligned comet image was a right mess, even after removing all the stars from every frame before running it. I literally painted a mask around the comet master (heavily convoluted)  and removed everything except the comet, set the empty background to median level, and then added it to the comet-less image. 

Have to say that the ability to quickly and efficiently remove stars at various points to check or correct the odd blemish was critical. Not sure how I'd have achieved anything much without the ability to do that.

I had similar last year when Comets 2022 E3 ZTF and 2022 U2 Atlas were close together. I managed to get DSS (and Siril) to stack the comets, stack the stars, but not both "frozen" in a single image. Starnet didn't remove the star streaks in the Comet stack, and the star stack had a green mess of a halo. It was far from perfect, but I didn't have Ha to deal with either! I might revisit it with PI at some point, this image has given me some inspiration 🙂

[ONIKKINEN]

Great comet image, adds a lot to the also beautiful nebulosity. I like the curved tail, makes it clear this is a moving object.

I feel your pain with the processing thing, i have tried comet imaging 3 times and hated the processing part each time. Each time i swore i would never do it again but of course i did and probably will again when the opportunity arises. But your image looks very nicely processed and not like a fistfight with photoshop these sometimes can (mine do at least).