octant
Date1749-1773
Inventory Number5251
ClassificationOctant
Subject
Maker
Edward Nairne
1726 - 1806
Cultural Region
Place of Origin
Dimensions46.1 x 37.2 x 7.2 cm (18 1/8 x 14 5/8 x 2 13/16 in.)
Material
DescriptionThis English octant is made in mahogany and has three index shades, three back sight shades, a dual peep sight, a 0 to 20' vernier divided into minutes (0 at the right), an arc on which is found a -2° 40' to 99° 40' scale, a mahogany and brass rotating index arm and finally an ivory pencil holder (with pencil missing). Three small removable legs were also added to the instrument so it could be lying down horizontally on a table when not in use.
In Collection(s)
Signedon nameplate inset in frame: Nairne No. 20 Cornhill / London
FunctionThe octant is a navigation instrument used to measure the altitude of the pole start at night or the sun at midday (hence the colored shades), in order to determine the latitude of the vessel in open water. It was also used to measure the position of the moon in order to find the longitude at sea using the highly technical lunar-distance method.
ProvenanceDavid Wheatland purchased from Alain Brieux, Paris, April 19, 1962 (lot 5/10). Donated to CHSI April 1977.
Gilkerson and Company
Date: 1809-1825
Accessories: stepped keystone oak box (black) with lock
Object number: 5300
Spencer, Browning, & Company
Date: 1843-1850
Accessories: box with key, adjustment tool, telescope, eye tube, eyepiece shade
Object number: 5248
E. & G. W. Blunt
Date: 1825-1860
Accessories: Keystone box (1996-1-0172b).
Object number: 1996-1-0172a
See also/See also
