@Stefan B Hi Stefan, thank you very much for evaluating that ASTAP stack. I will later respond in detail. For now: my impression and results are pretty much the same like yours. I guess, that's a good sign
Hi Mike, Ok, thanks - that means that I got it right.
Background is only, that I took flats and bias frames for use with DSS. All attempts using darks failed for me, the result was always worse than without darks. Somewhere I read, that the 2000D would have a low dark current and I my impression is that this is true. Maybe I will take darks in future, but for now this seems not to be the most urgent point. But I will most likely take flat darks from now on ...
Yes, I guess, I was a bit confused writing this description, but you understood, what I wanted to say I am quite sure, that I reloaded the bias frames into Dark flats, but perhaps - and I hope - I only messed it up or it had no effect. I cannot believe that double subtracting the bias frames would work. I will take a closer look, when I do this stack again without "Auto levels".Mike in Rancho wrote: ↑Sat May 07, 2022 5:52 pm Though I am a bit confused by your description of a "second run" with the Bias reloaded into Dark Flats. AFAIK if the master flat is already created those ought to be ignored? But if not, the calibration would be incorrect as the flats would be double bias-subtracted.
Thanks for your detailed description. I'm quite sure, I did things that way. But as said, maybe I messed something up. I will do that again with a little more calm, as you suggested and then report back and upload the new stack as well. So please don't waste time with the old stack.Mike in Rancho wrote: ↑Sat May 07, 2022 5:52 pm If you want, take your time with ASTAP and just step through things manually, one-by-one. That'll help to learn it, and every bit of software has a learning curve. Even ST, which you know, is made for beginners.
If you load your dark flats and hit analyze you can see the statistics for each frame. Then, same with the flats. Then there's a button that says replace flats and dark flats with master flat. This happens automatically if you just load everything and hit stack (and that's why your files "disappeared.") Next, same thing with your darks (or whatever you loaded into the darks tab). Finally, lights can be so analyzed, and the stats reviewed to see if you want to cull any bad shots.
Ok, I think I have to say goodbye to my theory it would be green because of of 2x G pixels on bayer pattern. Thank you for clarification! I will dive a little bit deeper into the things you explained. That sounds quite interesting ...Mike in Rancho wrote: ↑Sat May 07, 2022 5:52 pm Do not worry about 2x G making your images green. They are averaged, not added. This improves the green SNR a bit, however, and that can be taken advantage of in Synth L creation. Ivo takes care of that math, of course, because he's Ivo! Just open or a proper OSC compose will do it. Anyway, the green cast typically found in OSC has more to do with the channel response of the sensor and bayer matrix, where green tends to be the strongest.
That would be very kind of you! But I will first check things in ASTAP again on my own before wasting your time. Maybe tomorrow and then I will report back here ...
Best regards, Dietmar.