I was noticing some hot pixels that weren't calibrating out. I figured that, after a couple of years since I last shot darks, I was probably due for some new ones. That's cool, I thought, I can run those in the daytime. I checked that the
Oops, I thought, something is not right here, as I scanned the first frames. I cranked up the screen stretch in
As confirmation that this was due to a light leak, I can see the shadow of condensation on the camera window at the left side. Amp glow doesn't leave shadows, but light leaks do. The scope is capped, the lights are out, but daylight leaking under the dome skirt and into the ventilation openings around the mirror is getting to the camera. This is the view inside the dome:
The reason I got this is because I accidentally forgot to specify in
A lesson in how dark it needs to be to take darks, and how to find a light leak if you suspect one.