ASI220mm mini - low contrast images on ASAIR. This is not a 290mm successor

vladi

I recently replaced one of two 290mm mini cameras with the new 220mm mini model. I also own 174mm mini which I mainly use on OAG-L. At the moment, on ASIAIR with the latest public firmware, 220 is the worst ZWO guiding camera I used, despite my old 120mm mini which failed on ASIAIR again and again. I tried to use 220mini in two sessions. In the first one, I gave up and ran the session with 174mm as the guiding camera. The main problem is that 220mm produces very low-contrast images on the default "M" gain. Reducing and increasing the gain does not help much. The contrast stays low. I'm not sure if this is a problem in ASIAIR: I did not try it on a PC or Mac yet. I managed to sell 290mm at a good price, but I'm unsure if this was a good idea. There are more reports about problems with 220mm. Are there some efforts to address it?

w7ay

vladi The main problem is that 220mm produces very low-contrast images on the default "M" gain. Reducing and increasing the gain does not help much.

Did you try turning on dark frames during autoguiding? That could help the bias problem (but unfortunately not with the large pixels - why I won't touch the ASI220).

Chen

Kevin_A

vladi I find the 220mm mini ok for guiding. You have to use a gain of around 120-180 and darks are a must. I find the 220 and 290 very similar in contrast but the 290 is definitely better for guiding.