Is this amp glow or a light leak?

[Gumminess8083]

 

So, I was just starting out with my dark library for my new camera (ZWO ASI294MM PRO) and noticed that some of the frames had these effects at the edges. Upon doing some reading, this appears to be amp glow, which is totally normal.

 

My problem is the following:
What you are seeing is an integration of multiple dark frames (around 40, average without any normalization). In a single frame, the only thing you can see is that "sunburst effect" on the right, while the one on the left is only present in the final integration.

Furthermore, in the integration, you can also see some kind of light "glow" at the bottom of the image. Is this some form of light leak?

I have uploaded one of my dakrs and the integration here: https://drive.google.com/drive/folders/1u74qVQrwNeKHUZ4R-xrFOFRhbHjOmHZC

 

Thanks in advance for your help!

[Anthonyexmouth]

Left and right is Amp glow.  

 

[newbie alert]

22 minutes ago, Anthonyexmouth said:

Left and right is Amp glow.  

 

Technically it's electroluminescence as the amplifiers are at the end of every row

[The Lazy Astronomer]

Yep, that's all "amp glow" - looks exactly the same on darks from my own 294MM

What I would say though, is it looks like your offset is too low - the minimum pixel value in your single frame is 0, which should not happen

 

One of mine for reference (same gain, but 3 min exposure instead if your 1 min)

 

Also (and this may just be me being overly cautious about these things), but I'd remove your lat & long values from the FITS header of any FITS file you're making publicly available.

[Gumminess8083]

48 minutes ago, The Lazy Astronomer said:

Yep, that's all "amp glow" - looks exactly the same on darks from my own 294MM

What I would say though, is it looks like your offset is too low - the minimum pixel value in your single frame is 0, which should not happen

 

One of mine for reference (same gain, but 3 min exposure instead if your 1 min)

 

Also (and this may just be me being overly cautious about these things), but I'd remove your lat & long values from the FITS header of any FITS file you're making publicly available.

Thanks for your reply and explanation!

As far as I was told, the minimum value should be above 0 when you integrate all your darks using a minimum function instead of average.

This is my result when I stack the same files as before but with a minimum function:


Does this look correct, or should the minimum value still be above 0 even when integrating the darks with an average function?
For context, I'm shooting at 200 gain and 2 offset-

PS, thanks for the heads up about the FITS header. I didn't know it included such things!

edit: these were the settings I used to stack my darks this time around:

Edited October 17, 2022 by Gumminess8083

[The Lazy Astronomer]

3 hours ago, Gumminess8083 said:

Thanks for your reply and explanation!

As far as I was told, the minimum value should be above 0 when you integrate all your darks using a minimum function instead of average.

This is my result when I stack the same files as before but with a minimum function:


Does this look correct, or should the minimum value still be above 0 even when integrating the darks with an average function?
For context, I'm shooting at 200 gain and 2 offset-

Yeah, I saw the offset of 2 in the FITS header when I was checking the gain you used and thought it was a bit low, so checked the stats.

I think what you say is right, but I'm now confused how you can have a minimum stack with a minimum pixel value greater than the minimum value of a single sub 🤔 A value of 1.000 on the 14-bit scale should have read 0.00006 on the normalised scale.

3 hours ago, Gumminess8083 said:

PS, thanks for the heads up about the FITS header. I didn't know it included such things!

No worries, obviously we're all good people on this forum, but you never know who's lurking and I didn't want you to be giving away info that lead to some weirdo turning up at your house! 🤣

Edited October 17, 2022 by The Lazy Astronomer

[Gumminess8083]

7 hours ago, The Lazy Astronomer said:

Yeah, I saw the offset of 2 in the FITS header when I was checking the gain you used and thought it was a bit low, so checked the stats.

I think what you say is right, but I'm now confused how you can have a minimum stack with a minimum pixel value greater than the minimum value of a single sub 🤔 A value of 1.000 on the 14-bit scale should have read 0.00006 on the normalised scale.

No worries, obviously we're all good people on this forum, but you never know who's lurking and I didn't want you to be giving away info that lead to some weirdo turning up at your house! 🤣

Huh, I'm not too savvy on this sort of stuff, but this is kinda puzzling, now that you mention it... Maybe I will open a separate thread on this subject later today, although I don't even really know how I would phrase the question xD

Edited October 18, 2022 by Gumminess8083