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bad pixel map of brand new QHYCDD 178M

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#1 dron2015

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Posted 18 July 2019 - 01:40 AM

Ladies, Gents,

 

Just a few days bought brand new QHY 178M and here is its hot pixel map at room temperature. 5k hot pixels out of 6M sensor. is it really ok? 

zero cold pixels.

 

Here is the picture (cannot upload to CN in a reasonable quality for some reason)

https://1drv.ms/u/s!...N973tg?e=goPEnu

 

Thanks much!

 

Best,

Andrey


Edited by dron2015, 18 July 2019 - 01:50 AM.


#2 james7ca

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Posted 18 July 2019 - 03:20 AM

I think it depends upon the gain and the base exposure and obviously how hot the room temperature. Also, is this from a master integration or just a single file?

 

It also depends upon what you consider to be a hot pixel. On my ZWO ASI178MM I get around 5K with a "Hot Sigma" level of 7.5 using a gain of 270 (lowest read noise), a base exposure of 10 seconds, and with a camera temperature of around 65F. This is for a single file as I normally don't take darks at room temperature and thus don't really have many samples to combine.


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#3 pyrasanth

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Posted 18 July 2019 - 06:31 AM

Ladies, Gents,

 

Just a few days bought brand new QHY 178M and here is its hot pixel map at room temperature. 5k hot pixels out of 6M sensor. is it really ok? 

zero cold pixels.

 

Here is the picture (cannot upload to CN in a reasonable quality for some reason)

https://1drv.ms/u/s!...N973tg?e=goPEnu

 

Thanks much!

 

Best,

Andrey

Do the math- that's only 0.083% of the array-so unless they are all congregated in a big blob you have nothing to worry about. Just use cosmetic correction or a bad pixel map and concentrate on having fun with your camera and not worrying about pointless stats.

 

Edit- I also notice that you took this stat at room temperature. I don't think you would want to image at room temperature. Take another stat at -20 and note the difference. Your hot pixel count will drop.


Edited by pyrasanth, 18 July 2019 - 06:57 AM.

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#4 CharlesW

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Posted 18 July 2019 - 09:45 AM

It’s a bit like buying a new car, draining all the fluids out, and then asking if the performance is okay. Take your camera outside in the early evening tonight. Let it sit so the body gets heat soaked from the ambient temperature. Then at ten o’clock turn it on and cool it until you are steady at about 80% power. Then take your measurements. 


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#5 dron2015

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Posted 18 July 2019 - 11:02 AM

Thanks much for advices! Will test it cold and at different gain levels. it was 25 pics integrated.

 

Clear skies!

 

Best,

Andrey




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