Sensor Analysis on QHY165C

bwells
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Sensor Analysis on QHY165C

Post by bwells » Sat Sep 08, 2018 1:37 am

I am using SharpCap Pro 3.1 and trying to use the sensor analysis with my QHY165C. The problem I have is when I run the Sensor Analysis, it quickly reports "The exposure time required is shorter than the minimum exposure value - Sensor Analysis Stopped! Restart with lower light levels".

But, I have the camera totally covered, so I cannot reduce the light. What I see is SharpCap 3.1 sets the Gain to 255 (the highest value) and Offset to 204. And if I manually set the gain to 255 and Offset to 204, I see a totally white frame, even if I have the cover on the camera.

I tried using the latest drivers from QHY for my camera and I even tried using SharpCap 3.2. It looks to me like SharpCap should not be trying to max out the Gain and raising the Offset because if you set those too high, of course it over exposes. Can you please help me so I can use SharpCap Sensor Analysis?

I also tried using the ASCOM driver, but I get strange colors switching between green and red which does not look correct. i tried the idea on another thread about using ASCOM with a QHY color camera and trying different Bayer Patterns to match a RED color for a RED object the camera is pointed to.

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Re: Sensor Analysis on QHY165C

Post by admin » Sat Sep 08, 2018 6:52 am

Hi,

A few questions for you...

1) what mode are you in? 8 bit or 16 bit?
2) what is the gain range of the QHY165C
3) what is the offset range?
4) can you share a screenshot showing the full sharpcap screen when it has just shown the 'sensor analysis stopped' message so I can see what stage it got to

The initial setup for sensor analysis should set the offset to 10% of its max value and the gain on QHY cameras should be capped to 50db, since measuring at gains beyond that tends to show problems similar to the ones you are seeing. Not sure why those initial settings are no good in your case...

thanks,

Robin

bwells
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Re: Sensor Analysis on QHY165C

Post by bwells » Sat Sep 08, 2018 12:12 pm

I am in 16 bit raw mode
The gain range is 0-255
The Offset range is 0-2047

Note that for this attempt, my QHY165C is not on my telescope but simply on the bench.
Note also that a few months ago, I did manage to get a run of this to work, but the data was not correct. When I say work, I mean I did not get this error. But the "green X's were not a line and I was still just learning the program. Since that time, I have upgraded both the QHY SDK DLL, the USB driver and SharpCap 3.1. So going back might be a challenge but still an option.

A somewhat similar kind of problem is that for the thermal controls, SharpCap sets the "Cooler Power" to 255, the highest setting possible. In response to this, the camera stops cooling. It seems when cooling power is set to 100% power, the camera stops cooling. If I manually set the power to anything lower than 255, it cools. So again, SharpCap pushes the power to 100% and the Camera does not like this setting. So I can only use manual cooling with SharpCap and my QHY165C.

Attached is the photo you asked for just after the error happened which is within 2 or 3 seconds after pressing the "Start" button on the Sensor Analysis screen.

My attempt at doing the same with ASCOM did not give me this error, but it also ended with a table of zero gain settings and I dont think worked correctly. I was also wondering if I could manually take the measurements myself and "paste" those into the histogram brain to use if that is an option.
SharpCapQHY.jpg
SharpCapQHY.jpg (194.37 KiB) Viewed 980 times

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Re: Sensor Analysis on QHY165C

Post by admin » Sat Sep 08, 2018 4:16 pm

Ok, looks like for some reason the camera doesn't have sensible values for the controls like most QHY cameras have - for instance usually the gain is measured either in dB (0-50 or so) or 0.1 dB (0-500 or so). 0-255 is a raw value by the look of things. I will limit the gain to 100 if the max is 255 and we will see what comes out as the result (we may need to change the 100 to some other value).

I will test my QHY cooled camera to see if I get the same with manual cooling, but for now, can you just use auto-cooling which aims for a target temp and sets the power automatically?

cheers

Robin

bwells
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Re: Sensor Analysis on QHY165C

Post by bwells » Sat Sep 08, 2018 8:04 pm

I wonder if there is a firmware update I could get for my QHY. I am not even sure if I can update firmware. I purchased the camera in December, 2017.

The moment I set the cooling to auto, SharpCap sets the power level to 255 and for some reason, that causes the camera to turn off cooling all together. And SharpCap keeps the level at 255, so the temperature never goes down.

Just as a test, I tried using EZCap_QT to set the temperature and if I select auto using EZCap_QT, it sets the power to several power levels and some of those levels include 100%. If I manually set the power level to 100% in EZCap, the temperature decrease like you would expect. But when manually setting the power level to 100% in SharpCap (255), the temperature stops decreasing and gradually starts increasing as if the power was set to zero.

For now, I can use EZCap to control my temperature and use SharpCap for everything else.

It may also be worth nothing that the gain in EZCap is from 0 to 4020 and the offset goes from 0-2047.

I just experimented with the Thermal Control and found a way to get it to work. If I pick a set temperature that is close to the current temperature, SharpCap picks a power level under 100% (255). For example, if the camera is currently at 10C, and I put the target temperature to 8C, then SharpCap will set the power level to 230. Now, the current temperature gets to 8C, so I can lower it again to 5C and I can do this a few times and eventually, when the current temperature is close to the set temperature, SharpCap will not use a power level of 255, so it all works correctly. the problem only occurs when the target temperature is far below the current temperature when SharpCap sets the power level to 100% (255).

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Re: Sensor Analysis on QHY165C

Post by admin » Sat Sep 08, 2018 8:32 pm

Hi,

this sort of issue can usually be fixed by an update to the SDK for the QHY cameras - the trouble is that SharpCap is already using the most recent published version (May 2018 - http://www.qhyccd.com/SWHIST_SDK.html), so there is not a great deal I can do at the moment :(

When I test with my cooled QHY camera, 255 is max cooling (I can hear the fan slow down due to the load of the cooler). If I turn on auto then it selects 255 to begin with and then drops the cooling power as the temperature gets closer to the target. Unfortunately it sounds as though there is a bug in the SDK for your camera so that the power level of 255 counts as 'cooler off', but somewhere else in the SDK the code is saying 'not nearly cool enough yet - keep the power on 255'.

It may be worth raising these issues on the QHY forums to see if they have an SDK update coming soon.

cheers,

Robin

bwells
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Re: Sensor Analysis on QHY165C

Post by bwells » Sat Sep 08, 2018 8:57 pm

I will get in touch with the folks at QHY to ask them about the power level 255 question and verify that the SDK reports gains between 0 and 255 to see if that is what was expected.

You said you could try limiting the gain to 100 if the max is 255 and we will see what comes out as the result (we may need to change the 100 to some other value).

Is that something that would be easy for you to do? I would love to try your idea to see if it works.

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Re: Sensor Analysis on QHY165C

Post by admin » Sat Sep 08, 2018 9:01 pm

Hi,

yes, the gain limit thing is easy - I have made the change and it will be in the next SharpCap 3.2 build (within a few days). Hopefully the sensor analysis will run with that limit and if you share your results then I can work out how the 0..255 range maps to real gain values and perhaps have a better idea of how to set the correct limit.

cheers,

Robin

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Re: Sensor Analysis on QHY165C

Post by bwells » Thu Sep 13, 2018 7:18 pm

I thought I would check back about the update you wrote about. Is there an update to SharpCap with the change you made to the gain so it goes to 100 when set to 255 for my QHY165C? I downloaded 3.2 beta, and the first attempt seemed to work in that I got the green "x" in a line as expected. But then once I moved to the next step, it gave me the same error about minimum exposure being reached. So no joy yet! :)

Thanks!

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Re: Sensor Analysis on QHY165C

Post by admin » Thu Sep 13, 2018 7:21 pm

Hi,

the next version after 3.2.5747 will have the change you are looking for - probably by the end of the weekend.

cheers,

Robin

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