M31 from Kelling Heath

[michaelmorris]

Here is my effort on M31 taken from Kelling Heath on the Thursday night. It was a tad windy, but surprisingly the subs seem to have come out okay. What a difference a nice dark sky makes - I could never dream of getting this quality of image from suburban Worcester.

[Cath]

Das a nice image Michael!

[cloudbuster]

very nice mike! by the looks of this, your processing skills are very good !

[allcart]

Nice job Mike. This is deff my first target when I get my setup sorted. If I can get anything near this I will be chuffed.

[Gina]

Great image - nice clear dust lanes

[michaelmorris]

very nice mike! by the looks of this, your processing skills are very good !

The 'processing skills' come from following the techniques espoused in the superb Jerry Lodriguss CD 'A guide to Astrophotgraphy with a DSLR camera'.

http://www.astropix.com/GADC/INTRO.HTM

and from all the help and advice from SGL members on this forum and at various SGL star parties.

I'm really pleased with the result, although I can already see three areas for improvement.

1 - the sky background is a bit noisy

2 - the brighter stars are rather bloated - this is probably down to a combination of the high winds during image capture and my inability to isolate the brighter stars and the galaxy core during certain stages of processing. ... more reading, practising and writing down image processing steps.

3 - Framing - I've missed a bit off the edge of the galaxy. A mosaic of two images would have solved this.

[JamesF]

That looks lovely. Loads of data away from the centre, nicely controlled core and even M32 looks like a galaxy rather than a blown out star. Very nice.

James

[Gina]

Did you take darks, flats and bias frames?

[michaelmorris]

Did you take darks, flats and bias frames?

Yes.

[RobH]

Lovely capture and a great job with the processing Michael, one to be proud of.

Cheers

Rob

[Dave Smith]

WOW that has come out well. I'm impressed.

I've just tried an experiment that I think reduces that background noise without affecting the rest.

I first magnified the image so that I was just looking at background and stars only. The background seems to have just two colours or shades. In levels did Cntrl click on the darker shade which puts a point on the line, and then did the same with the brighter shade and then using the down arrow (rather than the cursor) move that point nearly level with the other. The rest of the curve then needs straightening out to avoid affecting other parts of the image. I hope that is understandable. What do you think?

Dave

[Moon monkey]

very nice ... Im going to Kelling Heath in November for a long weekend... hope I get some clear skys ;o)

[RobH]

WOW that has come out well. I'm impressed.

I've just tried an experiment that I think reduces that background noise without affecting the rest.

I first magnified the image so that I was just looking at background and stars only. The background seems to have just two colours or shades. In levels did Cntrl click on the darker shade which puts a point on the line, and then did the same with the brighter shade and then using the down arrow (rather than the cursor) move that point nearly level with the other. The rest of the curve then needs straightening out to avoid affecting other parts of the image. I hope that is understandable. What do you think?

Dave

I do something similar using colour select and levels Dave, and it works well. It's better to lighten the darker pixels rather than darken the light ones though, as you can easily lose faint detail if you do it this way.

Cheers

Rob

[michaelmorris]

Thanks for the tips guys, I'll give it a go and let you know how I get on.

[michaelmorris]

I've just tried an experiment that I think reduces that background noise without affecting the rest.

I first magnified the image so that I was just looking at background and stars only. The background seems to have just two colours or shades. In levels did Cntrl click on the darker shade which puts a point on the line, and then did the same with the brighter shade and then using the down arrow (rather than the cursor) move that point nearly level with the other. The rest of the curve then needs straightening out to avoid affecting other parts of the image. I hope that is understandable. What do you think?

Dave

Hi Dave,

I've tried your method and can concur that it's a great way of smoothing out a background. Thanks for sharing the info.

However, I've tried both options (lightening the darker elements and darken the lighter elements) but one washes out the nebulosity in the galaxy too much and the other clips the nebulosity in the galaxy too much.

So I'll stick with the existing compromise for now.

[RikM]

That is a very nice image Michael. A dark sky does make a difference doesn't it.

To help with the background, do you have Noel's actions?

If you make a duplicate layer, add a layer mask using the quick mask tool, copy the original image into the mask (alt+click the mask to activate it), and invert it, tweak the levels on the mask to make the background sky white and the galaxy and stars black, then apply a soft gausian blur to the mask (1-2 pixel radius). Click back on to the duplicate image again and run colour blotch reduction from Noel's actions and reduce the layer opacity to 80-90% to reduce the plasticy look. You might want to run a local contrast enhancement as layer on top, add a hide all layer mask then paint over the dark dust lanes to bring back some of the lovely detail you have captured.