Deep Sky Stacker creating weird coloured lines

[AlanP_]

Hi everyone,

I had the privilege of going up into the mountains away from light pollution in Gran Canaria recently. All I have is a kit lens and a Canon 600D but I tried to make the most of it and capture the Milkyway. I captured 30 light frames at 12second exposures (the max I can do with this lens). I forgot to take dark frames, however, I still have some Bias frames which I used. When I stack the photo in DSS, it creates weird coloured lines at random spots throughout the image.

It also creates or emphasizes some star trailing. Is there any way I can fix this? It is not very evident in the raw captures.

Thanks in advance.

[JohnSadlerAstro]

Hi,

There's nothing serious here--welcome to the world of hot pixel noise! Those dots are the hot pixels which are left in the image due to not taking darks. What has happened is that the stars have moved between subs, and DSS has countered that movement. However as a result, the hot pixels have changed position, leaving red, green or blue dots.

I'd suggest you take some darks at the same ISO/exposure settings as you used in the photo and stack with those, they should remove the streaks immediately. It may also help ease the star trail issues, DSS may have tried to align off the noise.

John

[AlanP_]

1 minute ago, JohnSadlerAstro said:

Hi,

There's nothing serious here--welcome to the world of hot pixel noise! Those dots are the hot pixels which are left in the image due to not taking darks. What has happened is that the stars have moved between subs, and DSS has countered that movement. However as a result, the hot pixels have changed position, leaving red, green or blue dots.

I'd suggest you take some darks at the same ISO/exposure settings as you used in the photo and stack with those, they should remove the streaks immediately. It may also help ease the star trail issues, DSS may have tried to align off the noise.

John

Oh damn it. I really should have taken darks  If I take them right now will it remove them if I use the same settings, or does it have to be the same temperature, place etc? I hope its the former because I'm back in Ireland now!

[JohnSadlerAstro]

Hi,

I shouldn't worry too much, for the very best results it should be taken at the same temps, however it isnt too critical and the location doesn't  matter. I've made a Darks library in the daytime at home by putting the camera inside its case with the "lid" on, and they seem to work fine. It should work with your pictures, too.

John

[knobby]

Or try editing the best single frame you have, the results might not be that bad .

[AlanP_]

37 minutes ago, JohnSadlerAstro said:

Hi,

I shouldn't worry too much, for the very best results it should be taken at the same temps, however it isnt too critical and the location doesn't  matter. I've made a Darks library in the daytime at home by putting the camera inside its case with the "lid" on, and they seem to work fine. It should work with your pictures, too.

John

Hi John,

I just took some darks, flats and bias photos and it has drastically improved the final photo. It's brought out so much detail and no weird glitching anywhere either. I appreciate your help!

[AlanP_]

1 hour ago, JohnSadlerAstro said:

Hi,

I shouldn't worry too much, for the very best results it should be taken at the same temps, however it isnt too critical and the location doesn't  matter. I've made a Darks library in the daytime at home by putting the camera inside its case with the "lid" on, and they seem to work fine. It should work with your pictures, too.

John

Final product. I'm happy enough with it considering it is my first, and I have just ordered a star adventurer mount too so I can take longer exposures!  Thanks again John.

[JohnSadlerAstro]

Hi,

That's a really nice shot, lots of dustclouds! Star trailing doesn't seem to be an enormous issue, although I think there's a bit of coma at the corners. I've got the same issue in my system, so more newt collimation! ?

I'm glad I could help!

John