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2600MC Pro Histogram

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#1 tkottary

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Posted 02 June 2020 - 09:32 PM

Hi All,

 

Could some one tell me whats causing these dual peaks in the histogram ? This is uniform across all type of lights(darks,bias, flats,lights,flat darks ).

 

Is this something  to worry about, I am still in the return window .

 

Raw and Masters Here

 

flatdark-2600.jpg

 

Thanks,T


Edited by tkottary, 02 June 2020 - 09:35 PM.

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#2 Jim Waters

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Posted 02 June 2020 - 09:58 PM

I get these too with my ASI2600MC Pro  My DSLR curves are different.  I am going to tag along and see what the reply's say.



#3 Jim Waters

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Posted 02 June 2020 - 10:33 PM

T - Join NINA Discord - 'Processing'.  They may be able to help you out.
 

http://discord.gg/fwpmHU4



#4 fmeschia

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Posted 02 June 2020 - 11:09 PM

I downloaded the file named "2020-06-02_15-33-29__-5.00_101_0.00s_0007.fits”. I am assuming it was a bias frame, given the 0.00s identifier. If I stretch it, I can definitely see a Bayer pattern, which is strange since I don’t think it should be there for a bias:

 

Screen Shot 2020-06-02 at 09.02.32 PM.png

 

This is also the origin of the three peaks of the histogram:

 

Image 6-2-20 at 9.05 PM.jpg

 

and as soon as I debayer the file, each peak becomes clearly identified with one color:

 

Image 6-2-20 at 9.05 PM.jpg

 

If this was actually a bias frame, something seems off to me. A bias frame should have received no light at all, so the CFA shouldn’t have any influence on the file.

 



#5 tkottary

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Posted 02 June 2020 - 11:32 PM

Yes that’s the bias frame . I just remembered there was an stc duo band filter inside spacecat when this testing was done . But not sure why would that affect dark and bias frames

#6 fmeschia

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Posted 02 June 2020 - 11:37 PM

Yes that’s the bias frame . I just remembered there was an stc duo band filter inside spacecat when this testing was done . But not sure why would that affect dark and bias frames

 

Is it possible that some light leaked in?



#7 fmeschia

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Posted 02 June 2020 - 11:40 PM

I guess not... I just examined the 300-second dark, the histogram is absolutely identical to the one of the bias frame. Which is also quite puzzling: where did the dark current and the dark noise go?



#8 tkottary

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Posted 03 June 2020 - 12:03 AM

I added raws for everything to the shared drive.

 

For the dark frames, spacecat cap was on and the whole image train was inside a towel. Only not covered part was the camera and m48 threads. So i am not sure that would cause the light leak. 



#9 tkottary

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Posted 03 June 2020 - 12:04 AM

I will post there If i find something related to Nina, granted all these captured with NINA.

 

T - Join NINA Discord - 'Processing'.  They may be able to help you out.
 

http://discord.gg/fwpmHU4



#10 Jim Waters

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Posted 03 June 2020 - 12:10 AM

Many of the people there use PI.



#11 deepanshu29

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Posted 03 June 2020 - 12:12 AM

I doubt NINA has anything to do with it. You have used same SDK/NINA setup for other ASI cameras (071MC, 1600MM). And I don't see double peaks with my QHY cameras (163M, 367c). This seems to be unique to 2600MC.

Edited by deepanshu29, 03 June 2020 - 01:43 AM.

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#12 fmeschia

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Posted 03 June 2020 - 12:16 AM

The interesting this is: assuming a bias frame actually sees no light at all, and so the same signal (in average) would be present in each photosite, then any emergence of the Bayer pattern can only be explained by accepting that the camera does some pre-processing of the data, with a different processing for each of the Bayer channels. So, not actually raw data.


Edited by fmeschia, 03 June 2020 - 12:17 AM.

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#13 tkottary

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Posted 03 June 2020 - 12:26 AM

Histogram of integrated file 

 

integrated-histo.jpg



#14 tkottary

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Posted 03 June 2020 - 12:27 AM

Histogram after ABE:

 

integrated-ABE-histogram.jpg



#15 bulrichl

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Posted 03 June 2020 - 03:45 AM

This issue is due to using the native ZWO camera driver and to the white balance default setting in the ZWO SDK, see e.g. https://www.cloudyni...e-white-pixels/ , post #5.

 

Set both WB_R and WB_B to 50 and apply "Save Config" or use the ASCOM camera driver.

 

Take new calibration frames after this change.

 

Bernd


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#16 Umasscrew39

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Posted 03 June 2020 - 03:58 AM

This is occurring with both the 2600 and 533 cameras.   The solution is the same for both....use the ASCOM camera driver as stated above.  I also found using the default WB R/B (95/52) or (50/50) makes little difference- either work just fine.  


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#17 tkottary

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Posted 03 June 2020 - 11:39 AM

Thank you Bernd. Not sure how i missed these threads. Its a pity ZWo is messing with the native driver. 



#18 Jim Waters

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Posted 03 June 2020 - 01:05 PM

Just getting back into this post.  This could explain some of the issues I have been having.  Just to be clear, are you saying that I should use the ASCOM driver on the ZWO site?

 

bulrichl - Are you saying to adjust the WB levels during processing - PixInsight?



#19 jtrezzo

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Posted 03 June 2020 - 04:42 PM

Histogram of integrated file 

 

attachicon.gifintegrated-histo.jpg

It's not red like that even after color calibration, is it?



#20 tkottary

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Posted 03 June 2020 - 06:03 PM

Nope, that was not unlinked STF.

It's not red like that even after color calibration, is it?

Unlinked stf was good.

 

unlinked-stf-histogram.jpg


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#21 bulrichl

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Posted 04 June 2020 - 07:03 AM

Just getting back into this post.  This could explain some of the issues I have been having.  Just to be clear, are you saying that I should use the ASCOM driver on the ZWO site?

 

bulrichl - Are you saying to adjust the WB levels during processing - PixInsight?

Hi Jim,

 

there might be good reasons to use the native ZWO camera driver - I don't know that, because so far I used only Windows and ASCOM.

 

In any case, if you use the native ZWO camera driver, make sure that the white balance parameters are set to WB_R=50 and WB_B=50 and save this setting in the config. Only then the raw data are saved in the FITS files.

 

If you use ASCOM and the ASCOM ZWO camera driver, you don't have to worry about it. The ASCOM driver will always save raw data to the FITS files.

 

It is also good practice to use one and the same capturing software and camera driver for all frames (lights and calibration frames) for a project.

 

Bernd




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