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geographical range
geographic range
greatest distance at which an object or a light source could be seen under conditions of perfect visibility, as limited only by the curvature of the Earth, by refraction in the atmosphere, and by the heights of the observer and the object or light source
Note 1 to entry: This entry was numbered 845-11-24 in IEC 60050-845:1987.
Note 2 to entry: This entry was numbered 17-488 in CIE S 017:2011.