SharpCap Forums

Hi,
I ran sensor analysis on my telescope pc then transferred the desktop\captures, roaming\sharpcap and local\sharpcap over to my desktop.
I put sample files in "https://www.dropbox.com/scl/fo/8t3wx9xv ... pt0u0&dl=0"
That contains a Light, a Dark stack, a Flat stack and copy of the SensorCharacteristics folder.

When I open the light image in SmartCap as a folder camera I can see m101, but no smart histogram.
I tried the test on the telescope pc and got the same result.

The INSTRUME fits value is "ZWO ASI2600MC DUO". The analysis file is "ZWO ASI2600MC~RAW16.json". The "SensorName" is "ZWO ASI2600MC Duo".
As an experiment I changed the analysis "SensorName" to "ZWO ASI2600MC", but that did not help.

Other aspects of the software seem nice to use.

Help?

Thanks
Web Dove

Hi,

I'm afraid that the folder monitor camera and the test cameras aren't smart enough to do what you are hoping they will do - they don't use the INSTRUME header from the source image files to choose the right sensor data file and enable the smart histogram. It would be quite a nice thing to add at some point in the future though.

The missing 'Duo' from the name of the file is correct - SharpCap removes suffixes like 'Duo', 'Pro' and 'Mini' as they all contain the same sensor, it's just the packaging that is different.

cheers,

Robin

Does this mean it is impossible to use smart histograms on existing images?

Hi,

yes, that's correct, sorry.

Robin

Hi Robin,

I see. If I capture images with SharpCap rather than NINA and I use my analyzed camera, will I be able to reopen those in SharpCap and use Smart Histograms?

Thanks
Web

Hi,

sorry, again no. I don't think it would even be generally possible to do it from another application, at least not unless you knew exactly which FITS headers the other application used for the necessary camera parameters *and* it saves all the parameters needed to perform the smart histogram calculation.

You can do a bit of a manual calculation - recent versions of SharpCap record the following FITS headers if sensor analysis data is available when capturing

RDNOISE - the read noise of the camera at the settings used for capture from the sensor analysis data
BIASADU - the ADU pixel value for no photons with the current settings
EGAIN - e/ADU at the true bit depth of the camera
EGAINSAV - e/ADU at the saved bit depth of the image (these two will be the same for 16 bit captures on 16 bit sensors)

For a 16 bit sensor like the ASI2600, take the mean background ADU of the image, subtract BIASADU, multiply by EGAIN and you get the mean number of electrons in the background of the image per pixel. For a well exposed image, that should be equal to or more than 10 times the RDNOISE squared.

if your sensor has a 12 or 14 bit ADC (and you have not turned on the saving option to save FITS without scaling the bit depth up to 16) then you will find that EGAIN and EGAINSAV differ by either a factor of 16 or 4, and you need to take account of the scaling of the data in the calculation. In that case the BIASADU header is also scaled up by the same factor, so take mean background - BIASADU and multiple by EGAINSAV to get the electrons count.

cheers,

Robin