I suspect you measure the FWHM width of the star - the size of the area that a single star covers on your sensor, to 50% of maximum brightness.
IE, if you have:
00001124742110000
The FWHM width would be 3.
000001393100000 FWHM would be 1 (or 1.7 or something)
You then multiple that number of pixels by the width in arc seconds, and you get your effective resolution limit in arc seconds. Divide that number by 2, and you get your maximum effective sampling resolution.
Quite a few apps out there will calculate the FWHM size, as it is also used as a metric to establish how good your focus is.
|