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Why does my fire capture image look like a chess board?

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#1 skydivephil

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Posted 27 May 2018 - 05:34 AM

I have previously imaged the sun using sharpcap but recently the frame is continually going to down zero almost immediately as I try and capture. 

Im running sharpcap on emulated pC on my mAc and so it was suggested to me using fire capture on the mac which I have finally been able to install. 

Yesterday was my first attempt . 

I have posted  an image below of what the sun looked like using my zwo 1600 colour camera. Good news was frame rates were high unlike shaprcap. But the preview image was hust weird like a chess board. When i tried to click on the preset sun image it made the screen go very small and then black . IM presuming its using less of the sensor and maybe the sun was not centred. But I think it was. 

Also the image was in monochrome, anyway to switch it to colour?

I tried my zwo120 camera and it seemed fine , so Im very puzzled as to what is going on. 

Any help most welcome. 


Edited by skydivephil, 27 May 2018 - 05:37 AM.


#2 skydivephil

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Posted 27 May 2018 - 05:36 AM

Screen Shot 2018-05-26 at 17.27.48.png


Edited by skydivephil, 27 May 2018 - 05:37 AM.


#3 ChrisWhite

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Posted 27 May 2018 - 05:42 AM

Most likely it is the Bayer Matrix Pattern.  Once you de-bayer your files in post processing, it goes away.


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#4 rigel123

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Posted 27 May 2018 - 06:18 AM

Hard to tell but it looks way overexposed.  The histogram looks strange and it appears from the screen capture that you had the exposure settings set for what you might use for Jupiter which would most likely be too long.  It doesn’t look like a bayer matrix as the checkerboard pattern looks too large.  Your screen capture doesn’t show whether you had “Debayer” checked on the options, but if it was overexposed as I suspect there would not be any color showing anyway.


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#5 skydivephil

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Posted 27 May 2018 - 07:09 AM

Hard to tell but it looks way overexposed.  The histogram looks strange and it appears from the screen capture that you had the exposure settings set for what you might use for Jupiter which would most likely be too long.  It doesn’t look like a bayer matrix as the checkerboard pattern looks too large.  Your screen capture doesn’t show whether you had “Debayer” checked on the options, but if it was overexposed as I suspect there would not be any color showing anyway.

 

My zw0 120 is also colour and didn't show any colour on the preview and didn't have the chess board look. Btw I have just found the debayer in the options menu so i will try that next time. 



#6 Midnight Dan

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Posted 27 May 2018 - 08:09 AM

Definitely the result of not using the Debayer option.

 

Your image is being downloaded to the software as a pure grayscale image.  The red, green, and blue filtered pixels all collect different amounts of light from the same target, so you end up with a grid pattern of gray scale pixels.  You can zoom in and see it.  When that image is downsized so you can see the whole thing on your screen, the algorithm that subsamples the pixels produces this kind of checkerboard pattern from the original data.  It's a bit like a lower frequency beat frequency that occurs when combining two different high frequency tones.  The combination of the original image's grid pattern, and the software algorithm's sampling pattern, creates a lower "frequency" dark/light pattern.

 

-Dan


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