I think this is a misconception. Calibration frames like bias or darks might be clipped on the left side of the histogram with offset 0. This could introduce artifacts during calibration.
jonrista.com/the-astrophotographers-guid...oise-and-histograms/
scroll down to "Anatomy of Signals in Histograms". The offset value prevents the "separation" of beeing negative.
Andreas
Read More...
© 2003-2022 by INDI Library. All rights reserved.