Eta Carinae widefield

[rmuhlack (Richard)]

Thought i'd have a go at a wide field shot of NGC3372.

This is 57 x 4min subs @ ISO800 using a modded 400D and a Nikon 200mm f4 AI prime lens @ f4 (plus darks, flats and dark flats)

Stacked in DSS and curves in Darktable

not quite as much of a wow factor as I would have expected from such a long exposure. I used median kappa-sigma stacking. would a different method (eg auto adaptive weighted average) produce a better result. Or is it just that I need to tweak the levels and curves a bit more?

Advice welcome

[Moon (James)]

Richard,
All up it's not a bad image. Focus & tracking etc look good.
Perhaps play with the colours in Photoshop to bring out the red a bit more?
How much light pollution do you have there?

I'm not sure about the best stacking method - but since you have soooo many subs, a simple mean should work really well.

James

[rmuhlack (Richard)]

Thanks James. As you said, I'm happy with the guiding and focus as well. Focus was checked with a Bahtinov mask (and so I have now confirmed that the hard infinity focus stop on that Nikon lens is indeed exactly at infinity). Polar alignment error using alignmaster was down to less than 1 arcminute, and as i've successfully guided subs twice as long with my imaging newt at 4 times the focal length i knew i'd be fine here.

Light pollution is minimal where I am (it is a rural area after all), however there is a slight sky glow from town, and as the imaging session progressed the subject was moving slowly into that glow. Could explain the red cast on the right hand side of the image? Anyway, will have another go with one of the other stacking options and play some more with the colours and saturation in Darktable (a linux equivalent of Lightroom).

If its clear again tonight I was going to try for a M8/M20 widefield - a subject away from the skyglow in a much darker part of the sky, so hopefully that will help!

[rmuhlack (Richard)]

had another go at L/a/b curve and saturation adjustment in Darktable. slightly improved maybe...?

[ZeroID (Brent)]

Second one looks better to me, more natural and better contrast. Seems to have more depth. Well done.