M51 and satellite

[Richard Thomas]

I was going through my subs of M51 from Monday night to get rid of any with planes, satellites etc when I came across this one.

Anyway I decided to keep this one  as I quite like the look of it and what are the chances of it going straight through the centre of the galaxy?!

[tomato]

Based on your image, and this one from me, it happens more often than you might think.

BTW, There is no need to throw them away, any stacking software worth it’s salt will fix satellite trails, even ones that go right through the object of interest.

Edited April 8, 2021 by tomato
Comment added re satellite trails

[Mr Thingy]

1 hour ago, tomato said:

Based on your image, and this one from me, it happens more often than you might think.

BTW, There is no need to throw them away, any stacking software worth it’s salt will fix satellite trails, even ones that go right through the object of interest.

For some reason, when I stack in DSS the trails remain, albeit fainter. I assumed it would scrub these as each particular trail is present only in 1 sub and therefore deemed as noise.

Maybe I need to change settings? I've been ditching about 10% of my subs due to trails.

[The Lazy Astronomer]

3 hours ago, Mr Thingy said:

For some reason, when I stack in DSS the trails remain, albeit fainter. I assumed it would scrub these as each particular trail is present only in 1 sub and therefore deemed as noise.

Maybe I need to change settings? I've been ditching about 10% of my subs due to trails.

What method are you using to stack the lights? I usually have a couple of subs with satellite trails and the kappa-sigma clipping method gets rid of them nicely with the default values

[tomato]

I’m afraid I can’t help with the DSS settings as I use APP for stacking, but the default Sigma clipping routine in this software sorted my satellite sub, no residual trail visible in the final image.

How many subs are you stacking?

[Seelive]

How many lights are you stacking? Idealy for Kappa-Sigma to work properly you need at least double figures. If most of your images have a similar overall intensity you could try reducing the Sigma value (from the default value of 3 to something less, say 2) but only just enough to remove the trail.

[ParallaxPete]

I was initially worried about Starlink trails after seeing how many would cross my field of view in Stellarium, but DSS seems to do a pretty good job of removing them using Kappa-Sigma clipping as mentioned above. I too had around 10-15% of my subs with trails but in end it wasn't an issue.

[Mr Thingy]

I stacked about 30 subs the other night and missed that one had a trail, which then featured in the final stack. Default settings (since I haven't yet researched what the various settings do!).

I will try changing some settings next time to see what gets rid of trails. 

Good to know I don't need to ditch these subs, particularly when they are 5 min each.

Edited April 8, 2021 by Mr Thingy