Darks with QHY183C Cool

[donboy]

Hi Robin,

Over last few days I have used three sets of darks for the QHY183C. Reason is they stop working properly. They initially work for a day or two then ampglow appears across the bottom and the top. The only solution I have found until yesterday was to redo the darks. What I found late last night, after having to redo my darks and they eventually failed as just described, was changing the ON switch for Debayer Preview to Force RGGB and that got the latest darks to work. Restarting SC and using ON for Debayer sometimes worked for Darks, but not all the time. I'm not sure that Force RGGB will work all the time, for ON position hasn''t.

Don

[admin]

Hi Don,

unfortunately I don't have a good, quick, answer for that... The 'On' setting for debayer preview should give identical processing to the 'Force XXXX' - providing you have picked the correct XXXX option. If 'On' is getting the wrong pattern then the images would look dreadful (purple splotchy areas or red/blue swapped) - that would jump out straight away.

Some thoughts that come to mind...

Is the cooling holding at the right temperaure? A temperature drift could affect darks.

Maybe there is a side effect of changing the 'Debayer' option - that forces a camera restart, which might reset something that is not quite working as it should (no idea what yet). If that's the case then switching to RAW8 and back would be expected to have similar effects

Try setting up to capture darks (right camera settings, no light, etc) with the old dark still being applied. If everything is good then the result should be a practically black frame with. If things are drifting off somehow then what you get will be the difference between the dark frames the camera is producing now and the ones it produced last time around - maybe looking at those with a stretch applied might help show something.

cheers,

Robin

[donboy]

Hi Robin,

For over a year I've been trying to resolve an ampglow issue with my QHY183C. I have sent it back to QHY twice and I still see the same issue (see dark frame and image pictures). The pictures will show ampglow across the full length of the top and bottom of the frame.

https://1drv.ms/f/s!AgjTpKA7s9ZYoCZCjrf ... W?e=54kdoT

All the time I've been using the QHY native driver in SC. I've tried various driver versions with the same results. Recently I tried using the QHY ASCOM Driver and low and behold the strange ampglow is not present. Finally success.

Any clue of what is going on?

Regards,

Don

[archer1960]

Have you updated the QHY driver package recently?

[donboy]

I've used all the recent recommended all-in-one drivers including beta versions. No difference.

[admin]

Hi Don,

given that the ASCOM driver gives an image without the amp glow, it seems likely that the ASCOM driver is initializing the camera with different settings than SharpCap. That could mean that the answer to the problem is lurking behind one of the controls on the right hand side in SharpCap, like 'USB Traffic', 'DDR Buffer', 'Optimize Camera For <Light Level>', 'Force Still Mode' or some other control - most likely showing up in the 'Camera Controls' section or maybe 'Misc Controls'.

I would set up the native version in SharpCap to capture darks with a strong stretch applied so you can see the glow. Set up the exposure/gain/etc (major controls) to match those you were using in the ASCOM driver, then try variations of the unusual controls to see if any have an effect on the amp glow effect in the captured images - probably worth letting it run a few frames after any adjustment as the QHY cameras sometimes have a delay between the adjustment being made and the result showing up in the image - can be a couple of frames, even at long exposures. This delay shouldn't happen with 'Force Still Mode' enabled though...

cheers,

Robin

[donboy]

Hi Robin,

Tried changing all kinds of settings as you suggested using the native driver and I still had this darn ampglow except for one setting. The 'Force Still Mode' setting I changed from OFF to ON and the ampglow on the top and bottom of the darks were gone. The Darks looked the same as the ASCOM driver ones.

So I think this setting has been the culprit all along.

When I get some clear skies I'll see how the native driver performs with the Force Still Mode in the ON position.


Regards,

Don

[admin]

Hi Don,

glad you found the right control - one thing to be aware of with the 'force still mode' option - on some models it changes the resolution by a few pixels in width and/or height, meaning that darks/flats captured without it on might not be compatible with those captured with it turned on. This is an underlying SDK thing that I can't do anything about sadly

clear skies!

Robin