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Not bad for a first use of new gear. What mode, gain and offset did you use?
It looks like too high a gain as the brighter stars are badly blown out. F5 is going to get bright quickly.
I also often use 300 seconds but basically the QHY600M boils down to:
1. Broadband use, ie. a regular colour image.
Mode 0 Gain 26 Offset 40. At gain 25 the read noise drops hence 26.
2. Narrowband images
Mode 1 Gain 56 Offset 50.
3. Objects with very bright stars or centre:
Mode 3 G 56 Offset 10
Super full well mode 3 2CMSIT (double sampling) this has 1.3 times lower read noise than the regular full well mode (mode 2). Full wells of the camera top out at 81,000 electrons in this mode which is right up there. The KAF16803 does 105,000 electrons, the KAF16200 does about 50,000 electrons so its a high level. In Broadband mode its only 20,000 electrons which isn't that flash and is more like a Sony ICX695 sensor which is similar. Super full well mode would have reduced your highlights from being blown out. Perhaps part of this blowout was processing and you stretched the image too aggressively. You may need to remove the stars and stretch the nebula and then add the stars back in later (I usually don't do that but many do and it does work if it all goes smoothly (which it may not).
I have started to shoot stars for colour with 300 seconds and broadband mode but any Ha, O111, S11 in narrowband mode above. Means 2 settings for a shoot (I often do HaLRGB). But that's just how it is with this camera.
These modes are very handy as they are not offered in the ASI version and after using the camera for a while I would not want to miss out on that functionality.
Greg.
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