M31 - At last it all comes together!

[Stub Mandrel]

I think I'm finally getting somewhere with DSOs.

Last night I managed to get 66 unguided 80-second subs of M31, took a dozen or more flats and darks.

I also managed to get a good combo of focus, focal length, exposure, polar alignment and the mount was tracking well with just the Bresser and the camera & lens (400mm) on it.

I would have tried a longer exposure, but I didn't want to risk wasting a clear sky. As it is a quick look says all frames tracked OK,

I need to go through and manually assess each sub and add bias frames, but this is the quick and dirty result. Any suggestions about how best to process this further gratefully received!

[Psychobilly]

I always chuck everything into the mix and then only check if there are any obvious issues in the stacked image..

Stacking in DSS...?

If you are,  with that number of subs use Kappa Sigma stacking,  it is the right tool for the job... It will even allow you to use subs with passing clouds and you won't have to worry about Aircraft , satellite or other UFO trails...

Peter...

[StuartJPP]

It is upside down for a start...the first thing I'd do is rotate it 180 degrees...that will make it look much better Sounds silly but it does make a huge difference...

Other than that there seems to be plenty of data captured in that image and some processing should bring out nice details and colour.

Good work!

[laudropb]

Nice image. Thanks for posting.

[Stub Mandrel]

I've used the Sigma stacking and upped the saturation -perhaps a bit too much?

Not sure how dark to make the background - I'm aware that the galaxy fades out over a huge area.

I'm sure it's the right way up - at least 'up' in this picture is within 10 degrees of the way 'up' it was last night - bear in mind cameras don't flip the image so it may be 'wrong' compared to a scope view :-)

[Psychobilly]

I'd say there are some issues with the colour balance and as you suspected the saturation has been  overcooked... In DSS where are the  RGB "peaks" in the histogram?

Peter...

[Stub Mandrel]

If I do 'background' they are one single aligned peak, if I do 'per channel' they are quite spread out blue, green, red.

I think the per-channel version polishes up more realistically, better star colours too, but M110 seems to be blue in the core...

Sorry if this png file is a bit big (7mb) I can swap for jpg if needed.

[davefrance]

It is upside down for a start...the first thing I'd do is rotate it 180 degrees...that will make it look much better Sounds silly but it does make a huge difference...

Other than that there seems to be plenty of data captured in that image and some processing should bring out nice details and colour.

Good work!

Upside down? I suppose it depends on where you are or what equipment you use to look at or photograph with, but from where I am standing it looks the right way up, not that there is a right or wrong way in space so I suppose it depends on personal preference.

[davefrance]

Just had a quick play with your file, there is definitely more detail in there, No doubt I will be told the sky is not that dark but I do like the contrast of M31 against a dark sky. Each to their own.

[Stub Mandrel]

Thanks Dave, you've brought out some of the ha regions!

I've gone back to the 16-bit data and flogged the gamma right up and then shifted the black point back across:

[davefrance]

Definitely showing more detail. Not sure what software you are using and I am definitely no expert but I would be tempted to lighten just the mid-tones and cut back a little on saturation.

[Stub Mandrel]

To my surprise, I think I've got the best results doing a bit more pre-processing in DSS:

[davefrance]

Looking good, I am sure someone on here can bring out more detail for you. I know many on here say don't process in DSS but I normally do a little bit of tweeking before saving and then use Paintshop Pro or AfterShot to finish off. Have had another quick fiddle with your pic, not sure whether its any better but here it is......

[Stub Mandrel]

You are a hard taskmaster Dave!

I've tried to balance the colour better, more like yours, and bring out the left and right parts of the disk.

I'm sure I'll keep coming back to this image, but I won't drag this thread out too far!

I really appreciate the advice I've been given, Dave & Peter, it really helps to see what others can do with my image, and then try and recreate the changes.

[davefrance]

Great stuff. Looks good to me.

You are a hard taskmaster Dave!

I've tried to balance the colour better, more like yours, and bring out the left and right parts of the disk.