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Old 14-04-2008, 06:45 PM
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Gama
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Join Date: Dec 2005
Location: Melbourne
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Sorry for taking too long to respond guys, but i had many other things to do..
Anyway, lets start with the "No Draks required". Well, thats about right for most images you will be doing.

Why, because as some of you had said, NOISE (Or lack of it). Noise is not just a slight difference in background. Its can be a MASSIVE difference. For those with a slow internet, i suggest you just look at the thumb nails at my site that compares a 10 minute dark frame from a QHY-8 and an image from the SBIG STL-11000M http://web.aanet.com.au/gama/qe.html .

For those that have high speed, then compare them here for the QHY-8 http://web.aanet.com.au/gama/images/...me600-QHY8.jpg and then the SBIG here http://web.aanet.com.au/gama/images/...2030%20sec.jpg .

This is why you need to take dark frames with the Kodak sensors. Thats not a starfield there boys.. Its noise, and it changes with temperature. This is why you need to match the exact temp when doing imaging with your exposures. So if you want a 2 minute image, you need to take a 2 minute dark. You want to image 3 minutes now ?, well, you need to re do a dark frame for the 3 minute frame. Because the QHY-8 has peanut shells worth of noise, it doesnt need to be set at exactly the same temp. Even if you have a temp difference of 10 or 20 degrees, its still never going to produce the noise the Kodak chips produce.
So this is why you dont need to regulate these Sony sensor cameras QHY, and in fact the Starlight Xpress cameras are also designed this way as well (Sony ccd chips).
Imagine just turning on the camera, leaving it cool down while you setup your scope, then attach and start imaging. No darks !, just dial in 1, 2 , 5, 10 minute exposures, and change the exposure the next frame, no need to do darks again for the different exposure.
Of course people that want to frame their work, or are perfectionists, then they would take a dark frame, but even so, the noise is not at the same levels produced by the Kodak sensors. In fact, you could count the pixels on one hand that have saturated. Sony are very stringent on dead pixels, and pixels that saturate withing a given time. There is more detail in terms of noise, but that is a few chapters in themselves.

Availability is high globally, and can take time to deliver. I do get large orders of them. They dont last long, word gets around pretty fast, and many dont believe the "No Dark Frames required" that many say. But its true !.

If there is any more info you need let me know guys.

Theo.
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