I need a little help if anyone has experienced this before.
This past week I went out to photograph the Veil Nebula, just to be mocked at by the weather gods and ended up with just 14, 2 minute subs of which I am using 13 (high success rate I guess).
I also took darks, flats and bias. 25 flats and darks and 60 bias.
I'm preprocessing as I have always done, but this time I get a completely dark image with some bright spots after light calibration. They are useless. If I integrate the lights without any calibration I succeed (but that's not how we do things). The only difference now is that I have only 13 subs instead of the 50 or more I usually have.
I tried different algorithms, tried without darks and without flats. The results are always the same. This never happened to me before (I am not a Pixinsight expert).
You can see the photo below the original FIT file (left) and after calibration (right). They are both boost stretched. I tried re-taking all flats, darks and bias to no avail.
I have a ZWO 533 Pro, OSC cooled camera.
Lights taken at 120 secs, gain 100, cooled to -8 c.
I thank in advance,