Can anyone save my M33 from last night?

[Priesters]

Hi all,

Just for background, my current processing experience is limited to what I can do when live stacking in SharpCap with an occasional tweak in GIMP.  Last night I was quite pleased with how the image was building with some basic stretches, colour balancing and a gradient removal but then just before I was about to pack up, my efforts were destroyed by 3 weighty satellite trails.  SharpCap has a new feature to remove them but for the life of me I cannot get it to work and having sigma clipping operating didn't work either.  It was at that point I realised I hadn't been saving the Raw frames so what I am left with is a stacked and semi-processed image with satellite trails.  Can anyone get rid of these awful satellite trails for me and maybe provide some instructions on how you did it?  For the record, lesson has been learnt about making sure the Raw frames are saved!

Thanks.

Andrew

 

Stack_16bits_9frames_5400s.fits

[Davesellars]

It's not perfect but I used Startools Heal feature... Line -> grow blob selection to create the mask - this seems to take care of the majority although it woudn't remove it entirely through M33 itself.  I'm sure someone perhaps better versed in Startools would make a better job of it though (I've only just come back to start using it again!!!)

 

[Priesters]

Thanks, that's much appreciated. 

After some considerable playing around I've managed to get SharpCap satellite trail removal working - I was being too hasty when adjusting the sensitivity/trail width settings so my laptop wasn't catching up with my fiddling 🙄.  Now I've got that working I think I'll stick to my basic processing and learn the more complex stuff when I've a bit more time on my hands.

[billhinge]

Best I can do, Pixinsight

Used  StarXTerminator to split galaxy and stars - star image had the trails

Edited the star image using clone tool - not as tedious as it sounds - I inverted image to black on white so the trails are clearly visible

Zoomed in really close, by repeated click and drop I was able to run along the trails quite easily most of the way, didn't take as long as you may think

re inverted when finished and did standard tweaking with crop dynamic background elimination, curves, wavelets etc

used pixelmath to put star and galaxy image back together

There is a linearPatternSubtraction script, it sees the lines but for some reason it doesn't remove them, hence plan B with clone tool

 

[ollypenrice]

Apart from the sat trails all you really need here are more subs. What you have is decent stuff and could give a very good image.

Olly

Edited October 2, 2022 by ollypenrice
typo

[Priesters]

3 hours ago, ollypenrice said:

What you have is decent stuff and could give a very good image.

Thank you.  I’m kind of hovering between AP and EEVA at the moment so have only captured images in one session and up here in not so sunny Lancashire my capture time is usually limited.  I guess I really do need to grasp the nettle and get in to capturing more subs over multiple sessions and let go of SharpCap for stacking my final images.  Out of interest, I’m assuming if I do capture over multiple sessions I’ll need to keep the camera angle the same or does stacking software sort that out?  I’m asking because I usually take the rig down after each session.

[ollypenrice]

18 minutes ago, Priesters said:

Thank you.  I’m kind of hovering between AP and EEVA at the moment so have only captured images in one session and up here in not so sunny Lancashire my capture time is usually limited.  I guess I really do need to grasp the nettle and get in to capturing more subs over multiple sessions and let go of SharpCap for stacking my final images.  Out of interest, I’m assuming if I do capture over multiple sessions I’ll need to keep the camera angle the same or does stacking software sort that out?  I’m asking because I usually take the rig down after each session.

Lancashire, land of my birth! Born in Wigan, schooled in Bolton, lived longest in Chorley.

You can stack images with rotation, certainly, and many of us do when we carry on after a meridian flip which gives images rotated 180. However, I always think it best to be aligned with RA and Dec. This is easy: do it by eye when putting the camera in then take a 5 second (ish) exposure while slewing slowly in RA or Dec only.  You'll get star trails at your present camera angle. Just rotate the camera till the trails align with the chip. You don't have to get it perfect.

Olly

[Priesters]

Cheers Olly, very useful tips.  My neck of the woods is closer to Burnley than your old haunts.

Btw, the image I shared was taken whilst stopping in a cottage near Hexham - quite jealous of the beautiful dark skies they have up there, could see the Milky Way very clearly.  I guess your skies are pretty dark too?

[ollypenrice]

1 hour ago, Priesters said:

Cheers Olly, very useful tips.  My neck of the woods is closer to Burnley than your old haunts.

Btw, the image I shared was taken whilst stopping in a cottage near Hexham - quite jealous of the beautiful dark skies they have up there, could see the Milky Way very clearly.  I guess your skies are pretty dark too?

Yes, extremely dark skies here but I chose my location with that as a first priority.

Olly

[alacant]

On 28/09/2022 at 20:12, Priesters said:

awful satellite trails

Hi

Amazing amount of detail for such a short exposure. Love it.

We'd recommend dithering between frames. If you've around 20 or so, you then stand a good chance of the trails being removed by stacking; use a decent clipping algorithm. 

Cheers and HTH

Edited October 2, 2022 by alacant

[Priesters]

7 minutes ago, alacant said:

Amazing amount of detail for such a short exposure. Love it.

Thank you.

Really appreciating everyone’s efforts with my data.  Actually, I might just keep posting stuff and leave it to you guys to process as that will save me loads of time 😂.