First, adjust the parameters that are already preset (e.g., telescope diameter, telescope focal ratio, beam diameter, etc).
The compute button will calculate all other parameters in the form. If you're curious how a number is computed, place your
The "pixel system throughput" times a source's spectral irradiance (erg s-1cm-2Angstrom-1)
will yield the total erg/s delivered in a pixel from the source. Such a number is valuable for computing (say) S/N ratios.