Accession No

6556

Brief Description

telescope, from “Sea Quadrant” navigational octant to design of Caleb Smith, English, mid-18th century

Origin

England

Maker

Unknown

Class

optical; navigation

Earliest Date

1734

Latest Date

1734

Inscription Date

Material

Wood (lignum vitae?); glass; metal (brass)

Dimensions

450mm (length) x 55mm (width) x 55mm (depth)

Special Collection

Provenance

Purchased from Tesseract, Box 151, Hastings-on-Hudson, New York 10706, U.S.A. on or before 16/03/2012. Item 17 in Tesseract catalogue 94, spring 2012.

Inscription

Description Notes

Telescope, from “Sea Quadrant” navigational octant to design of Caleb Smith, English, mid-18th century.

Telescope from “Sea Quadrant” made to a 1734 octant design by Caleb Smith, named the “Astroscope” or “Sea Quadrant”. Screws into 4 parts. Wood is very hard tropical wood, perhaps lignum vitae, and polished at every point except on the flat of the eyepiece. The largest part and the lens piece of the telescope are cracked; it is perhaps wood shrinkage that has caused one lens, between the main body and the lenspiece, to crack. Both ends of telescope are tethered and there is one small brass mounting pin to the side. Two sections hold original lenses. Still works; gives an inverted image at low power magnification.

Complete.

References

Events