LIMITATIONS FOR DAYTIME DETECTION OF STARS USING THE INTENSIFIER IMAGE ORTHICON

This paper presents an analysis of the theoretical limitation for daytime de-tection of stars. The paper deals first with the fundamental limits in detection as valid for an ideal device and then with the limitations for a device having a quantum conversion efficiency of less than one, as valid for the intensifier image orthicon. This type of camera tube was suggested by the author in 1952 for overcoming the noise in the scanning section of conventional camera tubes in order to reach the limitations in detection as determined by the noise of the photo-cathode, when using a sequential light amplifier system (U. S. Patent 2,955,158: Light amplifier, assigned to the U. S. government, inventor Radames K. H. Gebel, filed Nov. 1958, patented Oct. 1960). The development of the intensifier image orthicon was sponsored and monitored by the Aeronautical Research Laboratory at Wright Air Development Center, and most effectively carried out by the Radio Corporation of America Laboratories at Princeton under the guidance of Dr. George A. Morton (Morton and Ruedy, 1960). For mathematical simplicity, some of the equations derived are approximations. However, they suffice for determining a first approximation of an "optimistic detectable apparent magnitude, " which is the purpose of this paper. A rectangular distribution of the quantum density is assumed rather than the actual graded distribution, where the two have the same total value. Technical details con-cerning the intensifier image orthicon and associated circuitry are not explained since this has been presented in an earlier paper (Gebel, 1961)