Hi, I'm fairly knowledgeable about PixInsight, I've completed 5 or 6 images (happily) over the last 2 or 3 years. I'm using
version 1.07
I have a luminance image of NGC 6946, 100 minutes exposure at f7. When I attempt to do HDR with Median transform,
7 Layers, after Deconvolution, 10 iterations, I get very little effect from HDR, unless I use 1 specific star mask for
Local support in Deconvolution. If do not deconvolve, HDR behaves normally. If I uncheck Median transform in HDR, then
HDR behaves normally. If I deconvolve with no Local support, no deranging at all, HDR with Median has no effect. Changing
the non-linear stretch parameters in HT, before HDR, has no effect on pass or fail.
Has anyone else seen this? I completed a previous image of NGC 253 without seeing this. Is there a related bug report?
My only (dim) guess was that it might be caused by ringing around stars. However I tried using RangeMask and PixelMath
to "fill-in" the rings with the peak background value, and this had no effect. Deconvolution on this image has only a mild
effect, hardly noticeable on the curve in HT. The star mask that works leaves very faint ringing around some stars. A better
star mask, that leaves no ringing, causes HDR Median to have no effect.
I am posting because while I am willing to work around this, I seem to have zero knowledge, zero guesses, what the cause is,
which means I don't know what to change in my workflow. The 1 star mask that works was arrived at by pure luck, before I
even knew this issue existed. And as I said, that star mask leaves some ringing.
Thanks,
Steve.
