ASI183 MC Pro Amp Glow

[SB]

Hi Folks,
Suddenly getting AMP glow (more than usual) last night. Shooting Helix Nebula. ASI183 MC Pro cooled to -20C, Unity Gain 111, BIN 1, 120 second subs. Would expect this much Amp Glow at 300 seconds.

Using an Esprit 100 with ZWO Duoband filter.

30 Darks not removing Amp Glow in DSS.

Any suggestions on how to resolve this? Happened once before when shooting NGC 2023.

Many thanks.

Chris.

[gregbradley]

Your exposure is too short so the signal from the target is too weak showing up the amp glow more. A longer exposure overwhelms it quite a bit and the amp glow is less intrusive.

I am using 10 minutes Gain 111 -10C and only about 9 darks and it subtracts out well using an ASI183mm Pro.

No bias just darks. I used CCDsoft to create the master dark and to do the dark subtraction.

Are your darks at -20C?

Greg.

[SB]

Hi Greg,
Thanks for that info.

Yes my Darks are taken at -20C.

Chris

[Terry B]

Chris
I use a ASI183MM pro at -20deg. This should be similar though. One thing I have found that you can not scale darks with this CMOS camera (or any CMOS maybe?)
The darks have to be identical exposures. I use exposures ranging from 20 secs to 600secs and they all seem to be able to completely remove the amp glow.

I have attached 2 images. The first is a 600sec unprocessed exposure of a spectra. Only the middle section of the image has any light reaching the sensor so all of the radiating rays are caused by amp glow.
The second is a stack of 3 x 600sec exposures processed for the spectra. This means that most of the frame is just no signal. It is heavily stretched but there is no evidence of the amp glow left. There are other faults obviously but these are not relevant to me as I'm only sampling the spectra.

[cometcatcher]

Are you sure you didn't accidently use a different Bin setting? I did that once.