Sharpcap Sensor Analysis not completing

[julian489289]

Hi, I have an Altair Astro 294C pro cooled camera and I am using SC V3.2.6248

The parameters set for the camera are RAW14, 1x1 binning, 4128x2808, ser file and on. I have been using natural daylight on a cloudy day and the brightness levels appears constant. If I used an Ipad/screen, I still get the same issue. I am not using any filters just the camera connected to the scope.

When I start the analysis running, I repeatedly get a message pop up "Exposure getting quite long, consider restarting with brighter illumination". I then move the scope to point to a brighter area of the room. The program goes to Measuring ADU which seems to complete OK but with the illumination message repeatedly popping up.

It then moves to Measuring sensor linearity (ensure constant illumination levels for good results). Again appears to run OK and moves to Determining Gain range. This passes through the various gain levels but when it gets to 1778/3162 levels, the program fails with no change of illumination being made, with an error message "cannot adjust the exp to give required brightness, measurement failed, min exposure reached, reduce light level and try again".

This error contradicts the earlier messages not bright enough and keeping the same constant illumination throughout??

I have tried this 10 times today and never got passed the gain levels. What am I oing wrong and how can I get this analysis to complete??

Hope you can help, thanks

[admin]

Hi,

your best bet would be to update to the very latest version of SharpCap from the downloads page and then try again. I've made quite a few improvements to try to make that particular part of the analysis more robust since the version you are using.

Also, I'd like to point out that there's not really much to be gained by running your own analysis of that camera – SharpCap ships with a premeasured analysis set for that camera and my experience is that there is very little difference between different copies of the same model of camera.

Cheers, Robin

[julian489289]

Thanks Robin

I was hoping to use the analysis report in NINA to ascertain what best exposures/gain etc to use hence running the analysis.

I will update the software and see how that goes?

Thanks

Julian

[julian489289]

Hi,

I have downloaded the new version and have tried the analysis a number of times but with the same result but this time I get further to the dark analysis of the sensor and then the gain analysis afterwards.

I do want to try and use the smart histogram function but without the analysis I don't think this will work. I use NINA to image which has different gain settings compared to those that SC set, so couldn't use the smart histogram gain & exposure suggestions in SC. Is there somewhere that I can download the stock sensor analysis that Robin mentioned in order to use this for the smart histogram run in NINA?

Thanks for your assistance

[admin]

Hi,

Ah, OK, if you want to export the analysis to NINA then you are quite right that you need to do your own analysis (you also need a SharpCap pro licence to let you access the raw data of the analysis for use outside of SharpCap).

The best thing to do is to post the full SharpCap log from the latest version after the analysis has failed (and also any failure message you get). I will then hopefully be able to advise on what is going wrong.

thanks,

Robin

[julian489289]

Thanks Robin.

No worries, I have the sharpcap pro version.

I have looked for the log but cannot locate it. Do these logs stay saved after SC has been closed down and if so where would the logs be saved please?

thank you

Julian

[admin]

Hi Julian,

yes, the logs get saved - the easiest way to find them is to put this into the 'location' box at the top of a Windows Explorer window

Code: Select all

%LOCALAPPDATA%\SharpCap\logs

That will actually take you to a folder called something like

Code: Select all

C:\Users\<your windows user name>\AppData\Local\SharpCap\logs

The best thing to do is to sort the files in there by date - ones that have a sensor analysis attempts in them will be quite large since the analysis produces a lot of logging information.

Cheers, Robin

[julian489289]

OK, i have the log files.

The parameters set for the camera are RAW14, 1x1 binning, 4128x2808, ser file and debayer preview on

Error messages I get are;

Exposure getting quite long, consider restarting with brighter illumination (quite often pops up but process continues) and
Cannot adjust the exposure to give required brightness, measurement failed, min exposure reached, reduce light level and try again.

I have done around 5 attempts to get the analysis to complete. I think two got beyond the dark run with lens cap on but the others failed before this.

Below is the copied log file for all runs, hopefully sufficient for you to diagnose.

I hope you can help me Robin, I appreciate your time, thanks, Julian.

[admin]

Hi,

based on the info in the last couple of pages of the log, it looks like the brightness of illumination is varying significantly - looking at a log line like this

Code: Select all

Adjusting exposure, current is 0.4623, target is 0.65+/-0.025 (pedestal = 0),  changing from 66.63ms to 80.16ms

we can interpret that as

Current histogram peak is at 46%, aiming for 65%, so changing exposure from 66ms to 80ms

But in that last block we see (selected lines)

Code: Select all

Adjusting exposure, current is 0.5327, target is 0.65+/-0.025 (pedestal = 0),  changing from 27.08ms to 31.56ms
Adjusting exposure, current is 0.4754, target is 0.65+/-0.025 (pedestal = 0),  changing from 10.03ms to 10.84ms
Adjusting exposure, current is 0.4634, target is 0.65+/-0.025 (pedestal = 0),  changing from 41.90ms to 50.34ms
Adjusting exposure, current is 0.5465, target is 0.65+/-0.025 (pedestal = 0),  changing from 111.97ms to 122.57ms
Adjusting exposure, current is 0.4623, target is 0.65+/-0.025 (pedestal = 0),  changing from 66.63ms to 80.16ms

That means that the exposure needed for the histogram to be somewhere near 50% is varying between 10ms and 100ms.

Not sure what light source you are using, but avoid phone/tablet screens as they vary the brightness in response to ambient light. Artificial light is usually OK or natural light on either a clear or fully overcast day.

Robin

[julian489289]

Hi Robin

I have been using natural light with the scope situated inside the conservatory.

I find that to get the correct brightness initially, I have to point the scope towards the windows but when checking the gain levels if i use the same position for the scope the analysis fails. So I find that if I point the scope towards the inside of the house after the gain measuring starts I can get the program to continue a little longer but still ultimately fails.

Today (current log files) is very overcast and I have not noticed any change in brightness.

Should I be changing the position of the scope to reduce brightness levels as the analysis continues or should the program work in the same position?

Thank you for a quick response

Kind regards

Julian