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half-peak divergence, <of a projector, in a specified plane>
angular extent of all the radius vectors of the polar curve of luminous intensity in the specified plane having lengths greater than 50 % of the maximum
Note 1 to entry: This entry was numbered 845-09-30 in IEC 60050-845:1987.
Note 2 to entry: This entry was numbered 17-514 in CIE S 017:2011.