ZWO ASI533MC_Pro and Sensor analysis problems

[photosbykev]

Hi,

I've just taken delivery of my first 'proper' astro camera having shot with a stock DSLR for many years. The ASI533 will be used on the back of a WO 61 refractor for wide field work, typically 1.5 degree square FoV.

I set up to analyse the sensor using a EL flat field panel with a 2 stop ND filter across the front to lower the illumination level. After a few false starts changing the ND filter a few times to fine tune the lighting level I started to get some reasonable progress with the initial testing running ok. I managed to get the straight line of green crosses but the programme locked up during the 'measuring the linearity and setting to 1%' phase.

As soon as this message appears the progress bar under the histogram disappears, the programme reports a dropped frame and then just sits there doing nothing.

I'm running the latest beta version of Sharpcap downloaded today and also using the native Sharpcap zwo driver. What should I change or look out for before I try the routine again? Is there a log saved by the programme that I can refer to to see if I can spot the problem after the programme is closed down?

best regards
Kev

[admin]

Hi,

A couple of ways possibly of looking at this problem...

Firstly, at the stage you mentioned the exposure will be being set to quite a small value – smaller than any exposures set in the earlier phases anyway. Perhaps that is causing the problem? You should be able to see the exposure value that is being set as the exposure control should update to show it. You could try setting a similar exposure value manually to see if it has a similar effect of causing the camera to freeze up. It may be that tinkering with the 'Turbo USB' control could be enough to unlock the camera so that it runs cleanly at shorter exposures.

If that doesn't lead anywhere then it's worth rerunning the analysis with the log window open – the analysis puts lots of info into the log and it may reveal a little more of what's going on (or feel free to post the log here so that I can have a look at it).

Hope this helps, Robin

[photosbykev]

Thanks for the feedback Robin,

since posting this message I've managed to get the analysis to complete by changing from a EL flats panel to a cheap Huion LED light panel. Reading the messages I was getting during the failed attempts I got the impression the light level was too high so I was adding ND gel filters to the EL flats panel to reduce the light output.

After seeing another post on here I changed to using the Huion light panel that puts out a lot more light and just ignored all the warning messages and the analysis completed quite quickly. From memory the analysis started with a exposure speed of 1.35ms which is very short but I think the final results are typical for the ASI533MC-Pro camera.

Below is the screen capture of two analysis runs carried out back to back with the camera at -10c which you may of seen on FB?

If it helps for future development I have the logs of both successful runs.

The log for the failed run is also available, it looks like this is where it went wrong
Info: 15:08:34.2096979 Thread:Image Process Thread#29 SharpCap.CameraAnalysis.MeasurementEngineBase.AutoExposureAimFor(MathGrid frame, Double fractionalADU, Double fractionalADUTolerance, Double pedestalADU) :: Adjusting exposure, current is 0.6217, target is 0.65+/-0.025 (pedestal = 0), changing from 5579.37ms to 5770.12ms
Info: 15:09:03.9456093 Thread:Image Process Thread#29 SharpCap.CameraAnalysis.MeasurementEngineBase.AutoExposureAimFor(MathGrid frame, Double fractionalADU, Double fractionalADUTolerance, Double pedestalADU) :: Aiming for 0.65 +/- 0.025, currently 0.6539 which is fine.
Warning: 15:09:15.3136385 Thread:ASI Grab Thread#28 SharpCap.Cameras.ASI.ASICameraProxy.GetFrameData(Int32 timeout, BufferFrame frame) :: Fetching still frame from ZWO camera failed with ExpWorking, exposure is 5770.115, timeout is 11347
Info: 15:09:20.3142747 Thread:ASI Grab Thread#28 SharpCap.Base.DroppedFrameLogger.Count(DroppedFrameType type, Int32 count) :: Dropped frames : 1 of type ZWOTimeout
Info: 15:09:20.3142747 Thread:ASI Grab Thread#28 SharpCap.Base.DroppedFrameLogger.Count(DroppedFrameType type, Int32 count) :: Dropped frames : 3 of type ZWOFromSDK
Info: 15:10:51.8336822 Thread:#1 SharpCap.UI.SharpCapForm.SharpCapForm_FormClosing(Object sender, FormClosingEventArgs e) :: Main window closing.



best regards
Kev

[NeilG]

like you, I had similar trouble. See this post :-
viewtopic.php?f=5&t=2202

I finally got it to work with a starting exposure of 3.2ms - try something similar and see if it works.

Regards
Neil

[admin]

Hi,

Good to hear that you got it working. I have a plan that will change the way you set up the exposure for the analysis that should make it more robust – the idea is to encourage you to set up a light level that gives an exposure of approximately 0.5 seconds at minimum gain and then only measured gains that correspond to exposures above 1 ms.

Cheers, Robin

[photosbykev]

Hi Robin,

sounds like a good compromise for a lot of us newbies I use a EL flat field panel for shooting flats, typically 3 second exposure @ 0 gain but I do have a cheap and nasty Huion LED lighting panel which is usb powered (about £20 on Amazon) which is much brighter and adjustable so getting to 0.5 seconds for an exposure wouldn't be a problem.

regards
Kev

Hi,

Good to hear that you got it working. I have a plan that will change the way you set up the exposure for the analysis that should make it more robust – the idea is to encourage you to set up a light level that gives an exposure of approximately 0.5 seconds at minimum gain and then only measured gains that correspond to exposures above 1 ms.

Cheers, Robin