Quote:
Originally Posted by gregbradley
Good shot for 4x4. I use 4x4 for focusing but wouldn't use it for imaging. I don't think it gains that much in sensitivity for the amount of loss of resolution. That chip is very sensitive anyway - around 55-60% QE depending on the camera.
As far as flats go I think they are almost not needed with that chip although there is some gain.
As pointed out with a mechanical shutter you need about 3 seconds for a flat exposure.
I use twilight or dawn flats (mostly twilight) with a white T-shirt over the end of the scope and point towards the west. Usually go for 20,000 ADU and around 3 seconds. I take 3 exposures and use average to combine and subtract a bias.
Greg.
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Good advice Greg - thanks for that.