Two flight spare units for the ultraviolet photometers flown on OGO-4 for airglow and Lyman alpha studies. These are simple ionization chambers set behind filters of varying substances and thicknesses, typically lithium fluoride. Orbiting Geophysical Observatory 4 was launched in July 1967. The photometers were transferred to NASM by the Naval Research Laboratory in July 1982.
Transferred from the Naval Research Laboratory