Photoelectric ray to determine flying ceiling. Washington, D.C., June 15. To permit a ground observer to determine at what height flying is safe during days of fog and heavy overcast, Miss Elizabeth M. Zandonini, of the Radio Section staff of the Bureau of Standards, is shown with the balloon transmitting equipment. A photoelectric cell measuring light brightness is used to control the pitch of the radio signal transmitted from the balloon as it ascends. A graphical frequency recorder plots the pitch and hence [...] a measure of the light brightness as a function [...] height. The experiments are carried on for the U.S. [...]
Summary
A black and white photo of a woman putting something in a box.
Public domain portrait photograph, free to use, no copyright restrictions image - Picryl description
Tags
Date
01/01/1937
Contributors
Harris & Ewing, photographer
Location
Washington, District of Columbia, United States, 38.90719, -77.03687
Source
Library of Congress
Copyright info
No known restrictions on publication.