Quote:
Originally Posted by peter_4059
Marc,
I haven't used any Bias frames. How do you capture bias frames with a qhy8 given it doesn't have a shutter?
I've tried longer exposures (up to 6 sec) and still get the same result. According to the tests I ran last weekend the ADU count for 4 sec is between 15000 and 35000 (LHS to RHS of histogram) with average at about 26000. Would this suggest my flats are over-exposed?
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26000? Yeah...way to bright. Start around 10000 ADU. Note the exposure time to get that level. Shoot 40 of them. Rotate your light box if needed (10 at 90degrees, 10 at 45, etc...clockwise, you get the idea). Then shoot 40 darks/bias at the same exposure time. Plug your scope to shoot.
Then make your master bias then your master flat. When you calibrate your sub subtract the bias master from the flat master then divide the flat master into each sub and you'll get perfect seamless flat fielding, both illuminations and dust motes. If not try a brighter flat until you get the right levels.