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Old 29-09-2009, 01:59 PM
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leinad is offline
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Location: Perth, WA
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Originally Posted by avandonk View Post
Take a series of of bias frames and if they are relatively the same it is normal sensor bias. If there is a major difference it is EM interference.

How you get rid of bias etc.
Take flats and darks at the same exposure and temperature as your flats
Take darks at the same temperature as your lights.
Take bias frames as well if you need to remove noise from your lights with darks at a different temperatures.
Here is a single exposure at 1min at f/5 at 300mm with 1600 ISO corrected for darks and flats and stretched. 1.3MB

Here is a good start


Thanks Bert.

I took a series of Bias frames and they all have the same noise pattern effect. I have the camera away from any power leads, plugged directly to laptop with usb cable.

I did process the lights with x2 darks and offsets but the pattern noise is still present when overprocessing.

Thanks for the article link, I'll have a read later this evening.

Do you have another sample of that images without flats and stretched that shows pattern noise ?
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