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ASI183MM Amp Glow

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11 replies to this topic

#1 deonb

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Posted 20 September 2020 - 02:27 AM

I'm trying to dark-calibrate out amp glow on an ASI183MM.

 

I'm using Ha exposures at 300 seconds, binning 1. I've tried PixInsight, AstroPixelProcessor and DeepSkyStacker. No matter what I do, there is significant amp glow that remains.

 

Below is the best I can get it (APP).

 

You can see APP was able to reduce the amp glow a little from the single light frame (3rd pic below), but it's not enough to make the final image usable. Same for PixInsight (BatchPreprocessing) and DeepSkyStacker. All three apps are using defaults - though I played around a bit and couldn't make a real difference.

 

Is 300 seconds beyond the limits of what I can practically take with a ASI183MM before it gets oversaturated? Or am I still not processing it correctly?

 

 

Processed picture (APP). Ha, 13 x 300 sec (after blinking):

Bubble.jpg

 

Masterdarks (Ha, 4 x 300 sec):

masterdark.jpg

 

A single light frame (Ha, 1 x 300 sec):

LightFrame.jpg

 



#2 bobzeq25

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Posted 20 September 2020 - 02:39 AM

My amp glow on my 183s (I have both) calibrates out well with carefully done bias, flats, darks.  PixInsight set to _not_ optimize darks.

 

Personal opinion.  It's important to not take any shortcuts.  For example, I like doing PI preprocessing manually, rather than using BPP.  It only takes a little longer, and it's solved problems for me.

 

Don't ask me why.  <smile>

 

These were 10 minute subs.

 

https://www.astrobin.com/d876xh/B/


Edited by bobzeq25, 20 September 2020 - 02:42 AM.

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#3 imtl

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Posted 20 September 2020 - 02:46 AM

Same here. I do 360s and 600s Ha with the ASI183mm pro and I calibrate the amp glow out with no problem. Check your settings in PI and maybe you need to redo your calibration files. Make sure everything is the same temperature and gain and offset.

 

I agree with Bob. I do everything manual in PI to be able to control it.


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#4 deonb

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Posted 20 September 2020 - 03:36 AM

My amp glow on my 183s (I have both) calibrates out well with carefully done bias, flats, darks.  PixInsight set to _not_ optimize darks.

 

Personal opinion.  It's important to not take any shortcuts.  For example, I like doing PI preprocessing manually, rather than using BPP.  It only takes a little longer, and it's solved problems for me.

 

Don't ask me why.  <smile>

 

These were 10 minute subs.

 

https://www.astrobin.com/d876xh/B/

Do you perhaps have a reference handy that describes something close to the workflow you follow (like an existing YouTube video)?


Edited by deonb, 20 September 2020 - 03:37 AM.


#5 terry59

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Posted 20 September 2020 - 04:52 AM

I'm trying to dark-calibrate out amp glow on an ASI183MM.

 

I'm using Ha exposures at 300 seconds, binning 1. I've tried PixInsight, AstroPixelProcessor and DeepSkyStacker. No matter what I do, there is significant amp glow that remains.

 

Below is the best I can get it (APP).

 

You can see APP was able to reduce the amp glow a little from the single light frame (3rd pic below), but it's not enough to make the final image usable. Same for PixInsight (BatchPreprocessing) and DeepSkyStacker. All three apps are using defaults - though I played around a bit and couldn't make a real difference.

 

Is 300 seconds beyond the limits of what I can practically take with a ASI183MM before it gets oversaturated? Or am I still not processing it correctly?

 

 

Processed picture (APP). Ha, 13 x 300 sec (after blinking):

attachicon.gifBubble.jpg

 

Masterdarks (Ha, 4 x 300 sec):

attachicon.gifmasterdark.jpg

 

A single light frame (Ha, 1 x 300 sec):

attachicon.gifLightFrame.jpg

 

Were your lights and darks taken with the same gain and offset? I use PI and must create my masters manually. WBPP and BPP do not work for me. WBPP comes close but leaves the residual glow I get without my master dark having a pedestal of 250 added. Since darks remove the glow I'd practice creating a master that completely removes the glow then decide if bias and flats are appropriate with your camera.  One thing I've learned here is that there isn't a single approach that works for everyone with a 183

 

This is my most recent image with the 183M. The image has been rotated 180 degrees so look at the left side for any glow

 

smile.gif

Attached Thumbnails

  • ic1848 sho.jpg

Edited by terry59, 20 September 2020 - 04:55 AM.

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#6 Paulyman

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Posted 20 September 2020 - 05:16 AM

I have imaged up to 900s and the amp glow calibrates out just fine. I have a dark library at gain 53 and gain 111, each master was made up of 40 darks. I see you are only using 4 darks, I’d increase that.

I use lights, darks, flats and flat darks rather than bias.
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#7 imtl

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Posted 20 September 2020 - 05:44 AM

I have imaged up to 900s and the amp glow calibrates out just fine. I have a dark library at gain 53 and gain 111, each master was made up of 40 darks. I see you are only using 4 darks, I’d increase that.

I use lights, darks, flats and flat darks rather than bias.

Same here.



#8 deonb

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Posted 20 September 2020 - 05:56 AM

Were your lights and darks taken with the same gain and offset? I use PI and must create my masters manually. WBPP and BPP do not work for me. WBPP comes close but leaves the residual glow I get without my master dark having a pedestal of 250 added. Since darks remove the glow I'd practice creating a master that completely removes the glow then decide if bias and flats are appropriate with your camera.  One thing I've learned here is that there isn't a single approach that works for everyone with a 183

 

This is my most recent image with the 183M. The image has been rotated 180 degrees so look at the left side for any glow

 

smile.gif

 

Crap. Yeah, that was it!! Had 120 gain for darks, 139 for lights for some reason. It works perfectly now. Thanks!


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#9 terry59

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Posted 20 September 2020 - 06:02 AM

Crap. Yeah, that was it!! Had 120 gain for darks, 139 for lights for some reason. It works perfectly now. Thanks!

waytogo.gif



#10 bobzeq25

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Posted 20 September 2020 - 10:29 AM

Do you perhaps have a reference handy that describes something close to the workflow you follow (like an existing YouTube video)?

Absolutely.  I not only recommend it for this, I recommend it for a great deal more.

 

https://www.amazon.c...5/dp/3319976885



#11 Deesk06

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Posted 20 September 2020 - 11:33 AM

I am able to calibrate the amp glow out with my 183 no problem in APP. Try it again and try a few different settings. Did you change anything?


Edited by Deesk06, 20 September 2020 - 11:34 AM.


#12 lakerunr

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Posted 30 September 2020 - 08:48 AM

I'm wondering if ZWO has done something to improve amp glow and noise in the ASI183MM over time. I have two of these. The first was purchased 02/2019, the second 08/2020. The newer one still has amp glow, in the same general pattern, but it seems to be at a lower intensity level. I thought I might be able to use my dark library from the first camera with the second, but I noticed the patterns were not completely identical. When I started taking darks for the new unit (with SGP), I noticed that the noise in general (hot, cold pixels, etc.) seemed lower. SGP show the Max ADU of darks is also lower on the second camera.

 

Is this just difference between units, or has ZWO made design changes (hardware, firmware) to improve the 183's performance in these areas?

 

I also notice that the TEC cooler seems less efficient. It uses 10-20% more power (according to SGP and Pegasus Ultimate Power Box current readings) to achieve the same cooling level as the first unit. 

 

Any insights appreciated!




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