light and dark patches in this image - real or processing artefacts ?

[MikeODay]

In the image below of Barnard's galaxy there are very pronounced areas of dark and light across the frame.  Is anyone familiar with this area of the sky and if so, do you know if the effect is a true representation of this part of the sky or is more likely to be due to processing artifacts?

I'm pretty sure that the areas of dark in the extreme corners are partly (mostly ?) due to imperfectly corrected vignetting but I'm less sure about the other dark areas in the image.  

Cheers

Mike

[andrewluck]

I've attached a stretched DSS image generated from Pixinsight (which I see on your list of software). It's the DSSImageDownloader script hidden under Utilities. This does show some structure in the background.

Andrew

[MikeODay]

Oh that's great thanks Andrew.  It's good to know that my workflow is not messing too much with the raw data.

Cheers

Mike