#21  
Old 05-11-2020, 09:57 PM
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Peter Ward
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Originally Posted by gregbradley View Post
That's a bit of a worry. What are the problems with the 2 cameras?

Greg.
While I don't doubt Martin's experience, I've seen a few QHY600's now, with no QC issues. By the way I've updated the review with some more test data.

The only issue I am having with the camera is impatience: I'm waiting for some Precise Parts adapters to nail down squaring-on of the sensor.....I've decided compression fittings don't cut it. 60Mp shows even the slightest tilt.

But on the odd occasion when you do nail everything down perfectly with top-shelf optics in front, the amount of sky you cover using one of these puppies at the back end and with superb resolution to boot, is awesome.
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  #22  
Old 06-11-2020, 08:01 AM
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gregbradley
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I asked on Cloudy Nights if anyone had a problematic QHY600m. The responses were almost all that theirs was reliable with one that had some trouble.

One responder said make sure you have a 5 amp power supply separate for the cooler and a good USB3 cable as that can cause issues. I have read similar about the ASI6200mm about the need for an adequate power supply separate from other devices.

So it sounds like its not systemic.

61mp full frame does sound like a challenge to get square and all perfect. I saw posts about chromatic aberration showing up in FSQ images near the corners. The theory is that the 61mp small pixels are showing up aberrations not normally visible.

Greg.
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  #23  
Old 06-11-2020, 09:06 AM
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Camelopardalis (Dunk)
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Quote:
Originally Posted by gregbradley View Post
61mp full frame does sound like a challenge to get square and all perfect. I saw posts about chromatic aberration showing up in FSQ images near the corners. The theory is that the 61mp small pixels are showing up aberrations not normally visible.
Indeed, and this is to be expected with such a large chip with “small” pixels...with 9 micron pixels we were oblivious.
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  #24  
Old 25-01-2021, 05:44 PM
Martin Pugh
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Earlier post edited following more clarification from QHY.

Hi.

thought I would add some more information that I gleaned over the weekend from Dr Qiu at QHY direct. As a relatively new CMOS user, I wasn't aware of this, and if you are reading the spec on the QHY website you may be misled.

So, bin 2x2, does not yield 18bit output as it states on the website. This is under development however, so if you use the on-chip binning function it outputs 12bit, so you need to do it through the driver which will then output 16bits. Of course, this is ONLY relevant to the mono camera. You cannot bin 2x2 the colour camera, hence you have to acquire data unbinned and do software binning thereafter. I have been toying with this over the weekend and I am yet to see any improvement in SNR. I find it quite interesting in the Maxim DL help file that after using the Bin 2x2 command, you should rescale the image by a factor of 4 in pixel math. Whereas in PI, you only have the option of average, median, min, max in IntegerResample, which outputs an identical ADU value to the unbinned image.

Martin

Last edited by Martin Pugh; 25-01-2021 at 06:45 PM.
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