M15 attempt and a couple of questions

[billyharris72]

Hi all.

I'll start by posting 2 images , which I took last night. Both of M15, 10 second exposures (all unbinned), ASI1600MM and 130P-DS with a coma corrector. One is RGB and one LRGB. I noticed a couple of issues with these and just wanted to ask on the forum (I think I know the answer to the first, but want to be sure, and thought it might be useful as the question comes up a lot). 

1) Looking at the images I can see that the stars are relatively round to the edge on the left hand side, while on the right they become oval about 1/3 of the way to the edge. Is this what collimation error typically looks like? I did check the scope today when I got in from work and it was slightly out, so I reckon that's what it is, but thought it would be worth asking to make sure, and maybe useful to illustrate assuming I'm right.

2) While the LRGB image looks sharper and cleaner (less noise) most of the colour has gone. I much prefer the star colours in the RGB image. I did the colour in Astro Art, which does not seem to provide any way to tweak the intensity of the L level relative to the RGB part of the image (that I can find). Is there a way to "rescue" the colours in the LRGB image while benefiting from the improved SNR?

- Don't know if it is relevant, but when I hover over a pixel in the LRGB image it gives me the R, G and B values, but nothing for L. Is this correct?

3) If I can have a bonus question, does anyone have any tips on how to process globular clusters and galaxies with bright centres? Astro Art has a DDP filter that smooths out the dynamic range, but at the cost of colour richness. At there any other ways to do this that people could recommend?

Cheers,

Billy.

[billyharris72]

Solved the colour wash out issue - hadn't aligned the luminance channel! Oh, the joys of learning a new workflow