The data for this image is about about 4 years old but the processing continues to evolve.
It is a 30 hr luminance exposure with a BRC-250 scope and ST-X10ME.
The surface background of the galaxy is much fainter than the natural skyglow at the darkest sites and is only "visible" as the surface background is added to the skyglow.
The professional scopes have difficulties with this object.
http://blogs.discovermagazine.com/ba.../#.VDNXS_mSwa4
The first attachment is a conventionally processed image of the object.
The second attachment is skyglow subtracted which I developed a few years ago.
The third attachment is a pixel mapping procedure I developed in PI and is applied to the second attachment.
The pixel mapping curve for the procedure is shown in the final attachment.
Clear skies
Steven