Original Format: photograph: print
Description: Schematic drawing of complete spectrohelioscope setup with observer, with detail inserts showing eyepiece and optical train. Ink drawing printed on card stock, 4.25 x 3.25 inches, signed R. W. P. and dated 1928. This version published in Amateur Telescope Making, Book 1, p. 193. Porter Papers.
Caltech Archives ID: RWP3.1-3