|Only for SBIG ST7/8/9/10e Non AGB cameras.|
To compare images from different setups it is necessary to normalize (make mathematically equivalent) the important elements: CCD efficiency (QE), telescope aperture, angular pixel size, filter, and exposure time.
The most problematic element for comparisons is spectral QE, but because the Kodak CCDs in the ST-7/8/9/10 “e” non-ABG cameras have very similar QE it is relatively simple to compare skies based on images from these cameras. For these cameras, Stan Moore has defined a standard measure of electron flux for unfiltered exposures:
e- / arcsec2 / meter2 / second
The calculator below will automatically normalize your system and compute the standard sky flux. The basic equation is:
Standard Flux = (background_ADU – 100) * gain / (exp_time * angular_pixel_size2 * clear_aperture)
To use the calculator, simply change the appropriate fields to your particular values.