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Old 29-04-2015, 10:17 PM
gregbradley's Avatar
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gregbradley is offline
Join Date: Feb 2006
Location: Sydney
Posts: 17,164
Ah that sounds better. If you are not using darks then there is no need to have the temperature so stable (perhaps for bias but I doubt it changes too much).

I'd whack it up to max. -20C is pretty decent and in winter that could easily be -30 to -30C. I wonder if the read noise drops also with the lower sensor temps.

I get amp glow with the Trius as well. Its very minor. I think a lot of the guys on the QSI Yahoo site are new to CCD and they probably panic about things like that.

Good idea about a bias subtract when not using darks. I should try that.

I did use bias and flats with the AP Honders on the weekend though with the Trius 694. F3.8, 12 inch aperture and 77% QE with a super high 66% in Ha is gaining signal super fast. Mike has had easy for the last year or so with his AG12. It a good formula.

I think the smaller pixels of the QSI 690/ Trius 814 (9.2mp, 3.69 micron pixels) would work well with the Honders gives .66 arc seconds which by my reckoning is textbook ideal sampling. Especially with an AO unit.

The new QSI 6120 sounds interesting with 12mp and 3.1 arc seconds and 3 electron read noise (smaller pixels give lower read noise).

That would give .55 arc secs with the Honders. But with the small wells and the powerful 12 inch F3.8 light gathering I would be worried its too much of an experiment and it may give bloated overexposed stars. Not sure. Hard to find sample images so I'll give that a while to prove itself.

Its not encouraging to read the QSI only goes to 42,000 ADU peak instead of 65535 but then most of those levels are wasted anyway in processing.

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