QHY294M-PRO for Solar Imaging

Use this section to discuss "standard" Baader/Coronado/ Lunt SolarView/ Daystar, etc… filters, cameras and scopes. No mods, just questions/ answers and reviews.
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Simon2940
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QHY294M-PRO for Solar Imaging

Post by Simon2940 »

I am currently testing out the QHY294 Mono camera for its viability for solar imaging for those who want a larger sensor size.

So far, im not 100% convinced with it as the pixel size is 4.63um compared to the IMX174 with a pixel size of 5.86um.

On paper, the QE in HA is a lot higher than the IMX174 based cameras so this should have been better. Below are the results.

Taken using an Esprit 100 with a Daystar Gemini. The first image is in Chrom mode and the second is in Prom mode.

It would seem that the prom mode actually performed better than the chrom mode. Seeing was 3/5, but that's not what the test is about. It's to see how well the camera performs against an ASI174MM or QHY174 Mono.
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(No flats taken on the Prom version - Being lazy!!!)

Biggest notable difference (apart from the sensor size) is the settings. In Chrom, the gain has to be turned up a lot to retain a shutter speed of 16ms. 8ms on Prom mode with the gain turned down.

Anything higher than 20ms results in any movement, shake, atmospheric distortions being added into any stacked images. You would need to have such good seeing for this camera to really prove its worth. Incidentally, smaller scopes can mitigate the seeing. Since i dont have a scope smaller than 100mm, this test will have to wait until I get a SolarMax 90 DSII again.

Another issue to consider is the fact that the physical sensor size is MFT and for most blocking filters, this is just too big. I had to crop down in frame size to avoid seeing the vignetting. So for those with larger blocking filters, this wouldn't be a big issue.

The next issue to address is frame rate. At the largest ROI, i get 16fps which is okay if you have great seeing and limit the capture amount to 500 frames, but not so good if longer as too much time passes to get good captures, especially on any fast moving proms. I tested various ROI to get a maximum frame rate of 20fps which in my case is needed to get rid of the fore mentioned vignetting.

I will test this again when we have activity and when seeing allows it. I am not ready to call this yet.


SimonM
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Re: QHY294M-PRO for Solar Imaging

Post by SimonM »

Simon2940 wrote: Mon Mar 01, 2021 6:51 pm On paper, the QE in HA is a lot higher than the IMX174 based cameras so this should have been better.
The cells are 40% smaller (by area) so any apparent increase in QE will be reduced by this amount, too.

Simon


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