I was really displeased with how I processed the Western Veil the other day. This field is especially difficult because of all the stars in it obscuring the target. PixInsight’s StarAlignment reported over 50,000 stars, though I imagine the real count is at least double that.
I became very overwhelmed and frustrated the first time I processed this data, as the stars were just too much for me to reduce pleasingly with what I knew at the time. I did some searching and reading and learned a few tricks now, including using MultiscaleMedianTransform to remove large scale objects, using HDRMultiscaleTransform to bring the stars to a more uniform brightness so that dimmer ones can be masked properly, and carefully using StarMask to create a mask of star contours instead of cores. This allowed me to do morphology on the stars to reduce their halos to a point where they are not overwhelming the target. After a good few hours of fiddling and starting over multiple times, I think I’ve found a balance of star reduction without ruining the target data.
I don’t care much for the bicolor stars. I think for my next project I will not use the UHC filter, even though it will likely take a lot more integration time to make a decent image.