Quote:
Originally Posted by Shiraz
The 6303 would be a really good match for your big scope - would seem to be a good value swap for galaxy/NB imaging if you can deal with the blooming. Not sure it would be any better than your 16803 though, except for Ha imaging.
the 694 is not very well matched to your CDK, being better suited to ~1m fl scopes. You need not be concerned about the well depth though, since the 694 actually has more dynamic range than the 6303 when multiple subs are allowed. For example, adding 9x5 minute subs with the 694 will produce the same read noise power and signal as 1x45 minute sub with the 6303. The 9 subs with the 694 will allow 180,000 electrons before saturation, which is much higher than the 100,000 allowed in the 6303, so the 694 is the better chip for dynamic range. You just need to forget the old way of thinking and accept that short subs can be effective when you have low read noise. And of course don't forget that the 694 will be twice as fast as a 6303 with O3 NB data - it has way better QE at short wavelengths. It would be a very effective chip for your shorter focal length scopes.
regards ray
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In theory that is correct Ray but mated with an AO unit plus its high QE I think it still might be very nice on the CDK. Oversampled just means less sensitivity so you are not at risk of anything really except losing some of the sensitivity.
I kind of like the idea of a 6303 chip as well but it seems too similar to the 16803 except QE is slightly higher in visible and substantially higher QE for the 6303 in Ha.
Quote:
Originally Posted by Bassnut
just had a squiz at the 694 spec. Yes the pixels are tiny, but the QE is very good.
Then I saw the dynamic range, not good. Its well depth is only 20k  (vs 100k for 6303) thats as bad as the 8300 !.Sounds like trouble to me. |
Small wells can sometimes interfere when there are bright stars in the field. But there are hundreds of excellent images using the KAF8300 around. I think its more a matter of shorter subs if you start getting bright star bloat.
I agree though the 6303 with AO would be an even better match for the CDK although less FOV which isn't really an issue for galaxies but would be for nebulas etc.
Greg.