QHY5III174M mini [SOLVED] !

[sharpcapt]

QHY5III174M mini sensor analysis

Hi
I seem not to be able to do a Sensor Analysis on this one.

I did have problems years ago too with the 178c, but in the end managed.

It is on a USB 3 at maximum data transfer.

Set it as you ask at maximum settings i.e. Resolution 16bit etc.

It is set on a SCT 10" F/10 looking up today's white sky.


I also tried to skip Binning. Then I set it to 8 bit - no change.

Before starting I did set camera to:

Mono 8 or 16
1920 x 1200
1x1 Binning
Exposure 137 = 65% Histogram
Gain 0
Frame rate maximum
Offset 0
USB traffic 200 [USB3]
All the rest is off as normal.

I do get a nice narrow Histogram at 65% at beginning.
I must have tried 15 times and I am getting a bit fed-up - I do hope it is me!

Outside light - initially was too high - Sharpcap said to me - so I added one of those thick supermarket bags with internal white and it went down - therefore set it to ~130ms - 65% Histogram

Any help?

Regards
M

ps I do have latest SharpCap version - I tend to update as soon as possible.

[admin]

Hi,

I must admit that I really try to do the sensor analysis with a telescope attached to the camera (or with the camera attached the telescope – whichever way you want to look at it!). I either tend to use a C thread lens with an adjustable aperture which can be used to get the right exposure very easily or with no lens at all (you can just move the camera to point at a surface of appropriate brightness).

I think the best thing would be if you could send me some more information about where the analysis gets stuck and also a log file captured after the failure occurs. That would let me give some more detailed advice.

Cheers, Robin

[sharpcapt]

Hi
I now have camera on its own and found a surface to get 180ms at 65% at 8bit, then will try at 16bit
Next, I do not know yet.

... minimum exposure reached. Reduce the light level and try again.

Now back into telescope and used a layer of a 'black' thin bin bag and set it to 65% at ~410ms - they are both what it wants now.

It seems to work now and done the 'whites' [not the laundry ] - and now doing the Blacks - telescope capped.

I surely love SharpCap ... lets hope it does this too 'et voila'' !

[sharpcapt]

After it had done the whites, blacks and almost all the rest [uncapped telescope]. I ended up again with same warning.

I give up now.

I do have very little time these days.

Will try again another day

[sharpcapt]

... and after a 'long time' I managed to find the time and actually done it once!

I kept camera on the table with short USB3 lead and used a 'white cloudy' standard cover and also covered it a bit using one of my black blankets, just enough to be able to set it 65% ~ 300ms.

Since I did Mars 'test' on 17 Sept 2020 - silly me I did not do more takes - it was probably a 4/5 night but I had my mind in testing setup for Mars which I missed due to weather, I have not found one single night worth getting gear out!

It liked it ans started doing it.

Here is the result, which I find quite strange - maybe is me ... I am nota physicist !

What do you think?

Thanks
M

[admin]

Hi,

yes, I'm a bit surprised by the read noise values being very low once you get away from the minimum gain. If you have a look at the analyses published by for instance ZWO for their equivalent camera, you can see that the read noise never gets below about 3.5e, even at high gain (https://www.firstlightoptics.com/zwo-ca ... amera.html).

I wonder if the dark frames that are being used to measure the read noise are unexpectedly clipping once the gain is turned up a bit. Some qhy cameras have a rather odd way for the black level and gain to interact with each other, which I thought I had dealt with, but I only have the 178 model test with.

Cheers, Robin