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Help with Adaptive Pedestal warnings / clipping

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(@bstott_98)
Main Sequence Star
Joined: 3 years ago
Posts: 17
Topic starter  

Hi Folks,

When I run APP with adaptive pedestal enabled, I often (always?) get the adaptive pedestal warning window as well as messages like the following regarding clipping:

08:06:45 - 2) CALIBRATE: Adaptive Data Pedestal: enabled
08:06:45 - 2) CALIBRATE: performing calibration in 32bits normalized floats...
08:06:45 - 2) CALIBRATE: converting data to 32bits normalized floats...
08:06:46 - 2) CALIBRATE: Adaptive Data Pedestal set at: 1.755E-02
08:06:46 - 2) CALIBRATE: 193 pixels are clipping to 0.

 

How serious is this?   How do I diagnose and fix whatever is causing this?  I do have some shadowing from my OAG prism that appears to be well corrected by the flats, but maybe it's too severe?

I'm using an unmodified Canon 6D, images and darks are 150 sec, using flats + flat darks (no bias frames).

Thanks,

-Bret


   
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(@wvreeven)
Quasar
Joined: 5 years ago
Posts: 2121
 

@bstott_98 Hi Bret,

The warning shows that less than 200 pixels are clipping so that's not very bad. The clipping happens when the sky background in the lights is at a similar level as the darks and this can be prevented by taking longer exposures. Do you use a filter while imaging and, if yes, which one?

HTH, Wouter


   
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(@bstott_98)
Main Sequence Star
Joined: 3 years ago
Posts: 17
Topic starter  

Hi Wouter,

Thanks for getting back to me.   I am not using any filters.  

-Bret


   
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(@wvreeven)
Quasar
Joined: 5 years ago
Posts: 2121
 

@bstott_98 Hi Bret,

I see you use an OAG. What F-ratio does your imaging scope have?

Thanks, Wouter


   
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(@bstott_98)
Main Sequence Star
Joined: 3 years ago
Posts: 17
Topic starter  

Hi Wouter,

I’m imaging at f/10.  My scope is an EdgeHD 11”. 

-Bret


   
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(@wvreeven)
Quasar
Joined: 5 years ago
Posts: 2121
 

@bstott_98 So that may explain the clipping of the pixels. You may want to up your exposure time to 200 sec or more. Still, less than 200 clipping pixels is not very serious and may be ignored if you prefer.


   
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(@bstott_98)
Main Sequence Star
Joined: 3 years ago
Posts: 17
Topic starter  

Hi Wouter,

Ill give that a try. Sounds like I can safely ignore though too. Thanks for the suggestions!

-Bret


   
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(@nicholas64)
Red Giant
Joined: 4 years ago
Posts: 44
 

I get this as well then get some weird results which look Green or blue and nothing else, when I open these files in either siril, pixinsight or Nebulosity they look normal

If I don'tuse multiply scale but only add scale in normalization it seems all fine

I use the L-extreme and now the L-ultimate and the exposures are 10 minutes long, proper darks etc.

It's something that occurs at times with this version and the previous beta version, Windows 11


   
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(@wvreeven)
Quasar
Joined: 5 years ago
Posts: 2121
 

@nicholas64 Nick, can you post a screenshot of the green or blue image that you get? Do you make any changes to the settings in APP or do you simply load the lights and calibration data in tab 1 and then go to tab 6 and hit the Integrate button?


   
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(@nicholas64)
Red Giant
Joined: 4 years ago
Posts: 44
 

@wvreeven 

It's only after using add scale in normalization it actually works but the warning still appears.

 

The original image looks blue or mono colored when using multi scale in normalization

 

Yet when using that same image in the other apps it appears normal.

No idea why

Here is the stacked  image using the default settings in APP

Screenshot 2022 12 06 172113

 

Yet if you put that image in say, Nebulosity it appears normal

Just stretched ans auto colour balance

 

Screenshot 2022 12 06 172946

 

 

 


   
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(@wvreeven)
Quasar
Joined: 5 years ago
Posts: 2121
 

@nicholas64 Does it help if you click the openGL button to the top of the APP screen such that it changes to CPU?


   
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(@nicholas64)
Red Giant
Joined: 4 years ago
Posts: 44
 

@wvreeven 

No difference

I might reshoot my darks with this batch as they are over a year old and see how that goes but I have to say this is puzzling.


   
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