Ok, so here is an interesting experience I would like to share. Recently I started automating my sessions so I could image during the night and get some sleep as well. It did feel a bit awkward to leave all that equipment out in the bakyard during the night, so I decided to install a security camera, if only to feel better about it. It has an IR-mode for when it is dark, real handy.
So far so good. I had everything running and the first few nights went reasonably well. The only thing is that at a given time, guiding would fail because of a lost guidestar. At first I thought clouds, but after a few nights I could see a pattern: the time at which guiding failed was almost the same every night. I tried various things but nothing worked.
As the summer progressed, my targets where getting higher at the beginning of my sessions. And then last week I had everything set up, ready to go to bed. I turned on the security camera and then the guide image was being flooded by stray light. And then it hit me: the IR-light from the camera was ruining my sessions. I added my Lum-filter with IR-cut to the ASI120, and everything was fine again.
So there's my lesson: watch out with IR-security cameras. These things generate a lot or IR/NIR-pollution that can interfere with guiding. You won't see it in your images because most of the time there is an IR-blocker in the image train. But not in the guidescope/camera...
Edited by RJF-Astro, 19 August 2019 - 05:24 PM.