NGC7000 - plagued by blue halos and dodgy star

[Adreneline]

Hi Everyone,

This is primarliy NGC7000 along with IC5070 and IC5068 taken with my ASI1600 and Samyang 135mm lens - heavily cropped to remove the very worst of the blue halos (predominently on the left hand side of the image only) and the dodgy star shapes in the corners of the image (predominently top right!).

This is an RGB+HaO image. The RGB was processed separately and stretched using ArcSinhStretch to bring out the star colours. The RGB and HOO images were then combined in PixelMath and tweaked in PS.

CC welcomed, along with any thoughts on why the blue halos are predominently on the left hand side of the image.

Thanks for looking.

Adrian

[tony210]

Hi - love the dense star fields but as you say you are blue to the right and red to the left so I would look at gradients in the red and blue RGB data to correct - best wishes Tony

[Xplode]

It does definitely look like gradients.
I have a Samyang 135mm lens too and i also get bad stars in one of the corners, i think the only sollution is to adjust it with a tilt adaptor.

[Adreneline]

3 hours ago, tony210 said:

I would look at gradients in the red and blue RGB data

 

1 hour ago, Xplode said:

It does definitely look like gradients.

Thanks Tony and Ole. To be honest there was a marked lack of rgb data on this image - the clouds were against me - as ever! I will certainly take your advice and have a look at the rgb data again and see what I can find. I also wonder whether I suffer from the dreaded 'blue bloat' but I had hoped my UV/IR filter might help alleviate/correct that problem.

This image was taken with the Samyang but I also have problems at the moment with the ZS71 as well which suffers terribly from droop - the focusser is not at all good at holding the reducer once it is loaded with the ASI1600 and ZWO-EFW, and it plays havoc with the star shapes.

Thanks again for your advice.

Adrian