Sensor Analyzer not working with my camera

[Trust The Science]

Hi, I have an FLI ML4240BI CCD camera and I would like to know as much as possible about the quality, statistics, and possible defects of the sensor/camera. I do exoplanet transit photometric light curves. So I am trying to get some idea how I can improve the quality of the readings. I was told that Sensor Analyzer is a good tool for this so I tried it. Rather than taking a few minutues to process, I am finding that the process is taking many hours and it often crashes. I have yet to obtain a good report. It will send me message like (source is too bright) then it will tell me (sourse is too dim). For most of the time it just sits there and doesn't do anything. It will often sit in this state of not doing anything for hours, then I will check back on it to find a message that said it 'Failed'. A picture of what I am doing is attached. Perhaps the app is meant for CMOS and I am trying to use it on a CCD. I'm not sure what the problem is.

[admin]

Hi,

the analysis is really designed for CMOS cameras that can give a fairly high frame rate, but it should work with CCD cameras too (typically there is no adjustable gain on a CCD camera, so you will only get one data point for e/ADU and read noise).

Things to try include

* set an even smaller ROI to try to increase frame rate - maybe 256x256?
* Increase the brightness of the illumination, which will reduce the exposures needed to get a grey image and speed things up
* Ensure that the illumination remains constant throughout - in certain parts of the procedure, a changing illumination value can delay or ruin the measurements.

There are also cases where the process can get stuck due to the camera not exactly following the exposure lengths requested - one camera turned out to round all exposures to the nearest 0.2 seconds above the 1s exposure level, and that caused problems.

At the stage showing in your screenshot, we would expect a straight line on the graph on the right, but the lowest data point is clearly well away from the line that the others follow. That could be caused by illumination changing during that measurement stage - at least that is one possibility.

The best thing to do when it gets stuck is to share the SharpCap log with me - captured after it gets stuck. That usually has enough info in it for me to work out what is going wrong and have a good go at establishing why.

thanks,

Robin

[turfpit]

I successfully ran the Sensor Analysis on an Atik 314L+ CCD camera.

For illumination, I used a white sheet of paper. It was cloudy outside with the sun completely obscured which meant the illumination was even. ROI was small - I cannot recall the size.

sensor_analysis.JPG (30.47 KiB) Viewed 445 times

This was the result. Read Noise shown as 4.14e (manufacturer quoted 4e)

Atik314Lplus_sensor_analysis.JPG (37.61 KiB) Viewed 445 times

Dave