Comet Processing Help

I had a window of clear weather to get some data on comet C/2022 E3

The attached work in progress is a stack of 120 files each of 1 minute exposure with a OSC camera

I used Siril to align on the comet. I also have a stack of the stars without the comet.

I’ll combine these later.

How can I get rid of the star trails left over in the comet image?


Having a high number of subs, then playing with the high sigma rejection is the best we can do yet.

I never thought to do this before on my comet situations; I always just composited and cranked exposure down. This might be image-changing for some of my old exposures, so thanks for responding.

Is it possible and can it be useful to use starless on all r…fit before the last stacking ?

Try to play more with Siril’s Sigma values.

You can also import the starless image in Photoshop and play with Dust & Scratches filter that can remove all the trails.
It will also remove the comet details, but you can always mask and retrieve it back with History brush.

Eventually, you’ll be left with Comet image that needs to be stacked on top of the star image (assuming you have already made star image without a comet).

Ok, thanks! I tried with Siril and Gimp without great results, but it’s not so important.
From this

to this

(Pentax KS-2 , 180 mm)

I’d up those faint stars and sky to not be that pitch black, but that’s personal.
Great, you managed to catch a tail at least. I haven’t got a tail on my images. I used 135mm after all.

But I’m super happy because I literally had like 20-25 minutes to work out of 2 hours I spent outdoors, as the clouds were just coming. I had a few of those cracks of clear sky.

I’d up those faint stars and sky to not be that pitch black

I agree

as the clouds were just coming

Me too I had a bit this problem and the light of the moon too…

I answer myself: yes! :stuck_out_tongue_closed_eyes:

The script that I’ve used for apply starnett++ on all the fit is very easy:

requires 1.1.0
starnet -stretch -nostarmask
starnet -stretch -nostarmask
starnet -stretch -nostarmask
load …

Even if my result is not very different from the previous ones the fusion of levels with Gimp in this way is more easier (anyway remains a bit of a sort of shadow of the trails of stars after the stack of files"starlessed") .
Instead of Gimp you can also use Siril directly with Recompose stars and Gimp only after.