This facility calculates recommended times for twilight flat field exposures at Mauna Kea as calculated by the programme described in "An Exposure Guide for Taking Twilight Flatfields with Large Format CCDs", Tyson, N. D., and Gal, R. R., 1993, AJ, 105, 1206. (NB. I haven't tested it yet, this is a raw adaptation of Tyson & Gal's paper).
Note: "Readout time" is the time between the start of two consecutive exposures.