Quote:
Originally Posted by JohnH
Have a look at:
AstroPhoto Insight Feb / Mar 2008 which you can find here:
Quote follows:
"One way to test the quality of the flat field frame light source is to create a master flat field frame and create a second master flat field frame with the telescope or light
source rotated 90 degrees. The first master flat field frame is used as the test image
which is calibrated by the second rotated master flat field.
A good flat field calibrated test image is a uniform noisy image with no dark or light areas. A good test image histogram is a normal probability distribu
tion. The normal probability distribution is caused by at least three types of noise that are in the master flat field frame and the test image. The noise sources are photon noise, dark current noise and readout noise. A nonuniform light source causes dark or light areas in the test image."
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Thanks for the comments John. I don't think the light source quality is the issue. I think the intensity of the flat frames is the item in question. The length or duration of the exposure is the hard thing to get right. Once this has been scoped for my camera I think the panel will produce excelent frames which correct abberations in the light frames and don't tend to add a few from an over exposed or under exposed flat frame.
I'll keep at it when the weather clears and I can find the linear exposure for this camera.
Thanks John I will look it up and see what they have to say. Interestingly the internet is full of information on flat frames but some directly opposes other information. Looks like trial and error is going to be the best method. At least for me.