Quote:
Originally Posted by TrevorW
the gain setting was 12 offset 27 will try lower gain offset values- thanks
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Its more the mode.
Try gain 0 and offset 10.
Mode 2 is extended full well mode. That means you get really deep wells (to protect star colour and highlights) but still low noise.
That's the one I started using. It seemed to also reduce the horizontal lines these cameras seem to have in the background.
You gain about 50% more full well depth using the above. That is more important in my opinion than the read noise everyone seems to talk about.
One of my CCDs runs at 6 electrons read noise and you are hard pressed to notice much noise in the image. So perhaps an exaggerated importance is being placed on that.
I do see lots of CMOS images with all white stars which is lack of well depth and too high gain errors as well as too long exposure time.
I am finding 300 seconds pretty workable but look for highlights being blown out to show you need shorter exposure times. It could vary with the brightness of the target object. With my 183 I used 600 seconds and a different setting for narrowband than for regular colour imaging (higher gain to reduce the read noise which is more apparent in narrowband imaging, somewhat contrary to what I said above). Read noise is only important with narrowband imaging not colour imaging.
Greg.
Greg.