Octant

Octant

<< >>
Usage conditions apply
Downloads
Description
This octant, which probably dates from the late eighteenth century, has a mahogany frame and index arm. The boxwood scale is graduated every 20 minutes from 0 to 90 degrees and read by transversals to 2 minutes of arc. The top of the scale is numbered counterclockwise for zenith distances. There is also a back sight and a back horizon glass that can be used to measure angles greater than 90°.
Location
Currently not on view
Object Name
octant
date made
late 18th century
Measurements
overall: 7.6 cm x 37.8 cm x 46 cm; 3 in x 14 7/8 in x 18 1/8 in
overall: 3 in x 14 7/8 in x 18 1/4 in; 7.62 cm x 37.7825 cm x 46.355 cm
ID Number
PH.314493
catalog number
314493
accession number
204107
See more items in
Medicine and Science: Physical Sciences
Navigation
Measuring & Mapping
Data Source
National Museum of American History
Nominate this object for photography.   

Our collection database is a work in progress. We may update this record based on further research and review. Learn more about our approach to sharing our collection online.

If you would like to know how you can use content on this page, see the Smithsonian's Terms of Use. If you need to request an image for publication or other use, please visit Rights and Reproductions.

Note: Comment submission is temporarily unavailable while we make improvements to the site. We apologize for the interruption. If you have a question relating to the museum's collections, please first check our Collections FAQ. If you require a personal response, please use our Contact page.