A Comparison of Computed and Experimental Detection Ranges of Objects Viewed with Telescopic Systems from Aboard Ship*

Abstract

The relative range performance of approximately 80 telescopic systems of 18 different designs has been determined by statistical methods based on the results of a field test conducted from shipboard. The range at which objects are detectable from aboard ship is compared with the range computed from laboratory measurements of light transmission, magnification, exit pupil, and contrast rendition, using a method described by Hardy and the data of Duntley and Blackwell on the characteristics of the atmosphere and the human eye. The agreement between the results of the field tests and the computations is extraordinary. This is interpreted to mean that the most important factors were taken into account in both the statistical and computational procedures. This implies that if a visibility field test is properly conducted, the results can be expected to agree with those of simulated laboratory tests, and conversely, that properly constructed laboratory tests will yield data which predict accurately the performance of instruments in the field.