2600MM Darks with bright edges - Forums

Topic starter

Dec 11, 2023

I recently let my camera shoot darks continuously throughout a long period. I did all my master darks to build my library but was a bit surprised to see the results. Everything looks fine except for the 300s & 600s master files. The edge on the right side seems to have a sort of glow to it. Has anyone else seen this on this sensor, or could it be a result of letting the camera run for 24hrs straight (+/-)?

Temp set at -20, ambient about ranging from -5 to +2 approximately.

600s master

300s master

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Jan Erik Vallestad

Topic starter

Dec 11, 2023

Posted in the wrong section and didn't even realize that this topic was recently covered: https://www.astrobin.com/forum/c/equipment-forums/zwo-asi2600mm-pro/faint-amp-glow-in-an-asi2600mm-pro/

MARK Shelton

Dec 11, 2023

I took a new set of master darks with my ASI2600MM PRO using the gain 100 offset 50 setting and I get the same bright band showing in my longer masters- faint in the 300 second exposures and very visible, like yours, in the 600 second exposures.

I suspect that this must be a bit of amp glow and provided the darks calibrate correctly this should not be of concern. It is possible that it is never possible to fully eliminate amp glow however it only shows in long exposures.

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Jan Erik Vallestad

Topic starter

Dec 11, 2023

MARK Shelton:
I took a new set of master darks with my ASI2600MM PRO using the gain 100 offset 50 setting and I get the same bright band showing in my longer masters- faint in the 300 second exposures and very visible, like yours, in the 600 second exposures.

I suspect that this must be a bit of amp glow and provided the darks calibrate correctly this should not be of concern. It is possible that it is never possible to fully eliminate amp glow however it only shows in long exposures.

After the admins moved my post I saw the recent discussion about this issue. I didn't have these on my 533MM on any of my 300s masters, but neither did I shoot darks for such a long time non-stop either.

I'll rest easily knowing it's nothing to worry about.

Tim Ray

Dec 11, 2023

I think these MasterDarks look fine. It looks like they have been stretched as to view the glow. It looks like standard amp glow and the MasterDark should work during your calibration routine. What gain were these taken at? I have MasterDarks for gains of 0, 100 and 200 for NB filters at 0C and -10C. If it was a light leak in the capture of the subs, I would imagine that the effect would be much greater and penetrate further into the interior of the sensor…

CS Tim

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Jan Erik Vallestad

Topic starter

Dec 11, 2023

Tim Ray:
I think these MasterDarks look fine. It looks like they have been stretched as to view the glow. It looks like standard amp glow and the MasterDark should work during your calibration routine. What gain were these taken at? I have MasterDarks for gains of 0, 100 and 200 for NB filters at 0C and -10C. If it was a light leak in the capture of the subs, I would imagine that the effect would be much greater and penetrate further into the interior of the sensor...

CS Tim

I only did for gain 100, all light was blocked out, most were taken during dark as well. I only use unity gain, are there specific scenarios where 0 or 200 would be more beneficent?

And you're quite right, it has STF applied to it so it is over-stretched in order to see everything.

Loastro

Dec 11, 2023

Hello Jan Erik,

I have the same camera, et I saw the same thing a few time ago (at 300s exposure, whatever the number of frames).
I googled it, and several users were talking about the exact same thing. Despite what ZWO says, this camera exibits some amp glow at these exposure times.
In my point of view, no need to rise the exposure time to 600s as this camera has a negligible read noise, you can stack twice 300s exposures without any noise problem to get the same result than the half at 600s.
Of course depending on your computer it could be longer to pre-process if you shoot many many subs.

Laurent

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Jan Erik Vallestad

Topic starter

Dec 11, 2023

Hello Jan Erik,

I have the same camera, et I saw the same thing a few time ago (at 300s exposure, whatever the number of frames).
I googled it, and several users were talking about the exact same thing. Despite what ZWO says, this camera exibits some amp glow at these exposure times.
In my point of view, no need to rise the exposure time to 600s as this camera has a negligible read noise, you can stack twice 300s exposures without any noise problem to get the same result than the half at 600s.
Of course depending on your computer it could be longer to pre-process if you shoot many many subs.

Laurent

Hi,

Thanks for replying! Just glad there's nothing to worry about then.

I've doing 300s for a long time but it's hard to find any short and precise tests as to how they compare. Since I've already managed to get a number of subs at both 300s and 600s I guess I could do a stack of each just to check for myself if there is any appartent advantage to doing it or not.

Computing power isn't an issue though, I'm just going after some very faint stuff.

Artem

Dec 11, 2023

Hello Jan Erik,

I have the same camera, et I saw the same thing a few time ago (at 300s exposure, whatever the number of frames).
I googled it, and several users were talking about the exact same thing. Despite what ZWO says, this camera exibits some amp glow at these exposure times.
In my point of view, no need to rise the exposure time to 600s as this camera has a negligible read noise, you can stack twice 300s exposures without any noise problem to get the same result than the half at 600s.
Of course depending on your computer it could be longer to pre-process if you shoot many many subs.

Laurent

Hi,

Thanks for replying! Just glad there's nothing to worry about then.

I've doing 300s for a long time but it's hard to find any short and precise tests as to how they compare. Since I've already managed to get a number of subs at both 300s and 600s I guess I could do a stack of each just to check for myself if there is any appartent advantage to doing it or not.

Computing power isn't an issue though, I'm just going after some very faint stuff.

*** Hi Jan,
I have the same camera and also do 600s subs. I noticed the same behavior when stretching via STF (if you don't do STF, you won't probably see bright edges, or not to that extreme). So I decided not to worry since we all crop edges

Thanks,
Artem***

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