M42 redux and DSP raw conversion problem
5 months ago
Last month I posted an image of the Orion nebula, M42, that represented my first attempt at constructing a stacked image of a nebula. Although it is difficult to see in the size-reduced image I posted, there are small black halos around parts of the brighter stars in that image. I wasn't sure what was the cause of those halos, but now after some further investigation, I have discovered that their source is the raw conversion provided by Silkypix DSP. The problem originates in the Sharpness tab of DSP. Two of the parameters there are Outline emphasis with a default value of 13 and Detail emphasis with a default value of 75. In the past I always have left those controls alone. What I have discovered is that these default values are responsible for the dark halos around the stars. The halos went away when I changed to Outline emphasis = 0 and Detail emphasis = 100. Here is my redone image of M42 after that change to the 18 source images I stacked.