Limiting Magmtude Studies with the Image Orthicon.
William T. Powers · The Astronomical Journal · 1962
A major problem in determining limiting magnitude of an image conversion system is distinguishing faint stars from noise pulses. This paper deals with a simple theoretical treatment of signal- to-noise ratio in an idealized image orthicon. It offers suggestions for predetermining the probability that a given image is a star and not a noise pulse. The theoretical computations are compared with observational data. Also described is a method for reaching fainter magnitudes by suppressing effects of skylight, and some preliminary results of attempts to improve image readout in the image orthicon.