From the October 2010 issue

Tony Hallas’ Cosmic Imaging: Stretching your data, part 2

December 2010: If you process your image carefully, you won't leave traces of what you did.
By | Published: October 20, 2010 | Last updated on May 18, 2023
If you only darken the region you selected, however, others will notice the boundary between it and the rest of the image. Here’s where the technique of feathering comes in.
Tony Hallas

You’re now at a stage in your processing where the nucleus of Bode’s Galaxy (M81) became too bright. In astroimaging terms, it’s “burned out.” The art of darkening the nucleus area without leaving a trace requires three steps.