Comments on Optical Characteristics of a Proposed Reflectance Standard

Grover Trytten and Wayne Flowers Willow Run Laboratories, Institute of Science and Technology, The University of Michigan, Ann Arbor, Michigan 48107. Received 20 February 1967.

We would like to make two additions to the content of our paper.1

The "bidirectional"reflectance (percent) data given in Fig. 3 can be converted to the bidirectional reflectance units as used by Nicodemus2 if the solid angle of the energy source of the Perkin-Elmer model 21 spectrophotometer is known. This has been measured to be ~0 .02 sr (Ref. 3).

The goniometric data in Fig. 4 (of Ref. 1) were measured at a wavelength of 6328 Å.

We are indebted to F . Saiedy of the National Meteorological Satellite Center, Suitland, Maryland, for pointing out these omissions.

References 1. G. Trytten and W. Flowers, Appl. Opt. 5, 1895 (1966). 2. F . E. Nicodemus, Appl. Opt. 4, 767 (1965). 3. D. Earing and W. Ginsberg, private communication.

May 1967 / Vol. 6, No. 5 / APPLIED OPTICS 979