View Single Post
Old 04-06-2016, 02:13 PM
glend (Glen)
Registered User

glend is offline
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 5,745
Originally Posted by Shiraz View Post
Glad to if you think it would be useful, but it will take a bit of thinking and that seems to be getting harderer - this camera requires some new assumptions - some of which are not obvious. In the meantime, a few thoughts:

If you get to sky noise limited conditions, the 694 will win because of it's high QE and the 8300 and 1600 will come second. However, for broadband, the 1600 needs maybe 1 minute subs, the 694 needs 5 minutes and the 8300 about 20 minute subs to get to sky limited performance with typical gear under typical sky, so there are very significant ancillary equipment/mount implications in favour of the 1600 - a low end mount might do well enough, plus you can sell your OAG,ONAG,large pixel guider etc and get a cheap guidescope with a QHY5L2.

With 3nm narrowband imaging, the 1600 might get to sky limited in 10-20 minutes, but neither of the other two will ever get there (practically) under dark sky (from memory, I think it required about 6 hour subs for the 8300). That gives the 1600 a big advantage if the sub lengths are limited to maybe 30 minutes, since the 1600 read noise will not intrude into an image - there will only be shot noise - but the others will have read noise as well (lots of it in the case of the 8300). Images from the 1600 should be deeper than those from the 694 and much deeper than those from the 8300. In heavy light pollution, all of the cameras should make it to sky-noise limited performance with practical sub lengths, so the 694 will win (ie require less total integration time) due to it's better QE. But the 1600 will still have the advantage of needing vastly shorter subs than the other two.

The 1600 is not magic. Sky glow, shot noise and dark noise will still ultimately limit what it can do, just like the other cameras. However, it has such low read noise that it can operate in modes that are simply not possible with the other two cameras - and that opens up lots of new opportunities. But if you are conservative by nature, you can still use it the old way - long subs will just give you a higher res version of the 8300.
Ray that is enough of a synopsis for me, thank you. I was not fishing for a thesis.
Reply With Quote