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QHY168C amp glow- QHY says no- I say yes

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11 replies to this topic

#1 pyrasanth

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Posted 24 September 2019 - 09:31 AM

I've just created a new set of calibration frames for my QHY168C as recently it had the cooling repaired.

 

I integrated a selection of dark frames, sets of around 25 each, ranging from 30 to 1800 seconds.

 

The QHY168C web site advertises the camera as having no amp glow. I have attached a sub of 24 integrated dark frames (1800 secs)- not bias corrected- and you can see a lump of amp glow in the left hand side of the frame. Whilst I'm sure this will calibrate out I'm not sure what basis QHY are claiming that the 168C has no amp glow.

 

The frame is stretched so the glow can be seen but it is only 4-6 ADU difference at the most so probably not significant.

 

 noampglow.JPG


Edited by pyrasanth, 24 September 2019 - 09:34 AM.

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#2 petert913

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Posted 24 September 2019 - 09:55 AM

I doubt any sensor can / should claim "zero" amp glow.   That's what  calibration frames are for smile.gif


Edited by petert913, 24 September 2019 - 09:56 AM.


#3 Frabog

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Posted 24 September 2019 - 10:14 AM

My ZWO294MC Pro has this too therefore you should definitely take Dark frames Bias Frames and flat frames this solves the problem afterwards.



#4 jdupton

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Posted 24 September 2019 - 10:21 AM

Mark,

 

   I am sure the Marketing Message makes a number of assumptions that we as customer may not agree with.

 

   However, 4 to 6 ADU over the background in an 1800 second exposure stack is not bad at all. I am not familiar with the camera and don't know what gain you were running at but I might set a criteria that if the glow amounts to less than 0.5 e- which could be rounded to 0 electrons, then I might also claim "zero amp glow" with a clear conscience. Can you multiply by your gain (in e-/ADU) and see what you get?

 

 

John



#5 bobzeq25

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Posted 24 September 2019 - 10:25 AM

It's on the basis of their marketing department.  <grin>



#6 OrionSword

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Posted 24 September 2019 - 11:18 AM

Well have no amp glow in my 168C.  I wonder if there is some other setting that could make it more pronounced?  What transfer speed are you using on USB?



#7 cccha

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Posted 24 September 2019 - 08:12 PM

I am QHYCCD technology, I need a FITS format to judge it. Can you send it to my mailbox? Yes, under normal circumstances, QHY168C is zero glow. If this problem occurs, we will help you replace it with a new camera. My email address is cha@qhyccd.com, please contact me.


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#8 pyrasanth

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Posted 25 September 2019 - 02:31 AM

I am QHYCCD technology, I need a FITS format to judge it. Can you send it to my mailbox? Yes, under normal circumstances, QHY168C is zero glow. If this problem occurs, we will help you replace it with a new camera. My email address is cha@qhyccd.com, please contact me.

Thank you for your post. I have sent you an email with a Dropbox link so you can download a zip file containing dark files from 30-1800 seconds as well as a Bias file.

 

Best wishes

Mark



#9 pyrasanth

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Posted 25 September 2019 - 05:05 AM

QHY have looked at the files & have identified an amp glow issue. They have agreed to replace the camera which is great customer service. Thank you QHY. This type of service goes a very long way in helping chose a vendor for a next camera.


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#10 Kaydubbed

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Posted 25 September 2019 - 08:49 AM

My ZWO294MC Pro has this too therefore you should definitely take Dark frames Bias Frames and flat frames this solves the problem afterwards.

But with your camera it is been accepted by people doing hours of research over months [while they should have just been imaging!] that bias frames are a bad idea and flats and dark flats over a second are much better for calibration. 



#11 pyrasanth

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Posted 28 September 2019 - 02:08 PM

A new camera has been shipped out to me. It will be with me in a few days then I can retest.



#12 pyrasanth

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Posted 02 October 2019 - 09:26 AM

I received a new camera today & I will post an updated dark when I've tested the replacement. The results look encouraging as I see no glow on a single 30 minute dark.

 

I would like to take this opportunity to thank both Cha from QHY & Jan Soldan (the European distributor & repair centre) who sorted out a new camera very quickly & without fuss. This is superb service and will go a long way to picking the supplier of my next camera.........now where's my wallet?




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