Amp Glow

Questions and answers about processing in StarTools and how to accomplish certain tasks.
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sandconp
Posts: 32
Joined: Tue Dec 03, 2019 6:59 pm

Amp Glow

Post by sandconp »

I have a ZWO ASI AIR 183MC CMOS Camera which is known to have AMP Glow. I have added darks to my stacking process and I still have AMP Glow on the right side of my image. I tried to crop most of it out but you can still see it and I don't want to loose too much of the image by cropping out too much.

Anybody have any suggestions in Star Tools 1.8 that could help me remove this annoying amp glow which darks are suppose to take care of?
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hixx
Posts: 254
Joined: Mon Sep 02, 2019 3:36 pm

Re: Amp Glow

Post by hixx »

Hi sandconp,
did You make sure the darks were shot at the same temperature? What might have happened here is overcompensation by the mastedark. Depending on the stacker's math, assuming the dark glow signal is stronger (darks shot at higher temp and/or longer exposure time compared to the lights) than the actual amp glow, calibration will result in negative pixel values while subtraction of Light - Dark). These will get truncated to black (=0),causing Wipe to back off, creating useless amplification attempting to recover the "detail" hence causing white halos. This may be mitigated using the dark anomaly filter in Wiper (increase this to 7 - 10 pixels and see if any improvement occurs. Then increse further until no more improvement. Alternatively is to get the stack right and ensure the stacker does not create negative values (e.g. "Adaptive pedestal" in APP). Also, make sure to use as many darks as possible with a min number of 20-30, use median (or average for higher counts, with outlier rejection to create the Masterdark
hope this helps,
let me know how you get along,
cheers,
jochen
sandconp
Posts: 32
Joined: Tue Dec 03, 2019 6:59 pm

Re: Amp Glow

Post by sandconp »

I just realized that my darks were not taken at the same exposure length so I am going to re-do my stacking. I will let you know.

Thanks !
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