I think this image is out of focus, but more importantly, your telescope appears to be significantly out of collimation and/or your focal reducer is not well matched (possibly both). If you look at the image near the bottom left, the stars appear to be slightly out of focus, but they're reasonably round. Now compare this region to the top, right, and especially top right. See how the stars have significant coma (comet shapes)? As you move about the field away from the lower left, the stars increasingly appear comet shaped (clear sign of coma aberration). You might try to first remove your focal reducer and try a test shot again to see if it improves the flatness of the field. If it does not, you will need to tune up your telescope's collimation. Cheers, Doug
I agree. The image is out of focus AND out of collimation. This was the 1st test with my new ASI183mmPro. I'm still trying to get the best of it but Pixinsight is really confusing to use (maybe I don't have the PI gene). I have another better sets that I shall try to process later, and most importantly I'm trying to change the Analog motor focus I have now with myfocuser2 as advised by Stephane earlier.
Your feedback is always appreciated...
Celestron 9.25, WO Z61, Sky-Watcher HEQ5 Pro mount, iOptron SmartEQ Pro+, Raspberry Pi 4 Kstars-Ekos-Indi server, MyFocuserPro2
ZWO OAG with ASI120MM Mini guide, ZWO ASI183MM Pro, ZWO ASI533MC Pro, ZWO EFW (LRGBHaS2O3), Celestron f/6.3 reducer