This gnomon is like those used on the lunar surface by Apollo astronauts during their scientific and photographic tasks. A gnomon is a gimbaled rod mounted on a tripod so that the rod is always pointed vertically. When deployed on the lunar surface, the shadow cast by the staff indicated sun angle and, therefore, direction. The rod length and the painted scale provided a reference for estimating the sizes of nearby objects. Shades of gray on the rod ranged in reflectivity from 5% to 35% and a color scale enabled more accurate determination of rock and soil colors by comparison.
The gnomon configuration was a little different for each Apollo flight. This particular gnomon was qualified for flight, but never used on a mission. It is similar to the one used on the later lunar missions (Apollo 15, 16, or 17) because it has both gray and color scales mounted to the tripod leg.
NASA transferred this to the Smithsonian in 1974.
Display Status
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.
Object Details
Country of Origin
United States of America
Type
EQUIPMENT-Photographic
Manufacturer
NASA - Johnson Space Center
Dimensions
Overall (deployed): 2 ft. 7/16 in. × 1 ft. 8 7/8 in., 0.6lb. (62 × 53cm, 0.3kg)
Other (stowed): 1 ft. 8 7/8 in. (53cm)
3-D (Storage/Transport Container (empty)): 62.9 × 13.3 × 12.4cm, 2.3kg (2 ft. 3/4 in. × 5 1/4 in. × 4 7/8 in., 5lb.)
Materials
Carbon-rich steel
Inventory Number
A19750133000
Credit Line
Transferred from the National Aeronautics and Space Administration
Data Source
National Air and Space Museum
Restrictions & Rights
Usage conditions apply
For more information, visit the Smithsonians Terms of Use.