Quote:
Originally Posted by ericwbenson
Hi Pete,
Take a short series of bias frames every night. See if the artifacts come and go (electronics flakyness or interference?) or are related to ambient temp. If the pattern never changes it's in the chip and you can calibrate it out.
Does the STX have the readout register on the side? I know the ST4000 did. Those single pixel dark streaks look like they are from hot pixel bleed (quite common in KAF chips), they are only found in columns. So either the image has been rotated 90 deg by processing, or the readout register is on the side.
I've attached a sample master bias frame from my camera (Apogee U16 with KAF16803, readout register at bottom), scaled down 25% and screen stretched to 1 ADU range (i.e. black = 1406.4 ADU and white = 1407.4 ADU) this is from 48 bias frames at -30C. The black lines are from non-uniformity in the readout register itself.
Good luck,
EB
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Eric
I must have missed your post yesterday.
What you present is precisely what I see in my bias frames. They don't vary from night to night.
If its the readout register itself, then presumably you calibrate them out. Do flats and darks alone deal with this or do you have some form of defect map applied as well?
Pete