Dark nebulae with a DSLR

[Leeps]

I took my first shot of a dark nebula over the last couple of nights and struggling with DSLR noise/"colour mottle". I can usually accept that the background has a bit of noise, but when it's a dark cloud of dust I want to be able to show it with as little noise as possible. My usual processing methods of masking out the light objects and denoising doesn't help here because they're obviously... dark. 

Any tips or am I asking too much from my gear and old DSLR? I was looking at the idea of dithering, but honestly the objects move a lot over the sensor due to unguided tracking errors at the moment anyway, so I don't think I'm really introducing correlated noise. 

The shot in question and capture details are here: https://telescopius.com/pictures/view/60833/deep_sky/by-lee_davison

[wimvb]

Nice image. I think that with some carefull processing, you should be able to separate those dark clouds from the background. Which processing software do you use?

[michael8554]

The notes on the image say Flats 20 x 10 sec ?

I would aim for exposures of around 1 sec with mid-range histogram.

What are ISO 400 exposures like ?

Michael

 

[Leeps]

On 22/05/2020 at 00:05, wimvb said:

Nice image. I think that with some carefull processing, you should be able to separate those dark clouds from the background. Which processing software do you use?

I've been doing some fairly amatuer use of pixinsight. I'd be happy to share the data and see what other people might be capable of!

 

On 22/05/2020 at 00:14, michael8554 said:

The notes on the image say Flats 20 x 10 sec ?

I would aim for exposures of around 1 sec with mid-range histogram.

What are ISO 400 exposures like ?

Michael

 

Yeah I shot them in twilight, and 10s was needed to get the histogram to hit the middle. I did shoot flats the day after, but I think the sun was too bright and angled into the scope so it gave me a hot corner of the image. I reshot these, and it seemed to clear it up. 

I can try shooting ISO400, I';ve been shooting at 200 due to the indication here. They got the research from here. I'm a little confused about it overall, but followed the advice since I don't want to waste clear nights. I can try 400? 

[michael8554]

Ah, one of those linear ISO response cameras.

I'd go with what that excellent site says.

Michael

[Leeps]

I tried 1 min subs on my new image, and I seem to either have much better noise performance, or the neb I was shooting is just brighter... I can't decide. Image is here: 

https://telescopius.com/pictures/view/61230/deep_sky/dumbbell-nebula/by-lee_davison