Sextant

Astronomy

Accession Number: 2012.ast.2

Description:

Sextant, 4 telescope/optical attachments in a fan shaped wooden box. Sextant is painted brass (black) with wooden handle, angled with unpainted graduated arc below and mirror, ring mount for telescope attachments, and filters above. Ring mount has adjusting brass knob and grooves for telescope attachments. Mirror is adjacent to ring mount, faces away from ring mount (if the sextant is held in the right hand) and slightly cracked. Adjacent to the mirror are 4 coloured glass filters for reflected light from the mirror. Adjacent to the filters is mounted an oval glass piece, split in two. One half is a mirror angled to reflect light from the primary mirror to the ring mount. The other half is clear to allow direct observation through a telescope attachment on the ring mount. Adjacent to the split oval lens are 3 more coloured glass filters for direct light from a distant observation. The graduated arc covers roughly 60 degrees and is marked 0 to 145 on one side and 0 to 5 on the other. Finely inscribed increments between these numbers may be read using a magnifying glass attached to the measuring arm of the sextant. Measuring arm moves along the graduated arc as the top mirror is adjusted and has a movable viewing space marked from 0 to 10. Three of the telescope attachments are threaded to fit in ring mount, fourth is a loose componant lens. Telescope attachments vary in length and lens aperture. Engraved on the graduated arc is “Troughton & Simms London”. Repair label, “Riggs & Brother”, pasted over and obscuring earlier label on inside lid of box.

Alternative Name:

Primary Materials:

Sextant and parts: Brass (painted black and open), glass and wood. Box: wood, iron (nails and hinges), woven fabric.

Markings:

“Troughton & Simms, London” on graduated arc. Label on inside of box: “Riggs & Brother. Transit Observa… Established in 1820. Successors to W. B. C. Riggs. 244 So. Front near Dock, Philadelphia. Chronometers. Clocks. Watches. Nautical Instruments. Books. Charts. &c. N.B. All kinds of Nautical Instruments Repaired.” In pencil on inside lid: “U. of Toronto”.

Dimensions (cm):

Sextant: 29.5 x 25 x 10.4; Attachment 1: 19 x 2 (diameter); Attachment 2: 13.5 x 2 (d); Attachment 3: 9 x 2 (d); Attachment 4: 9.5 x 2 (d)

Function:

Measuring angles between distant objects. Used in navigation, astronomy and surveying.

Condition:

Fair but functional. Some insect damage on repair label. Tarnishing on graduated arc – fingerprints. Mirror slightly cracked, glass filters scratched. Entire frame has been scratched with paint worn off. Corrosion of nails and hinges used in box. Box has large crack on the bottom and is scratched all over.

Associated Instruments: 2011.ast.01, 2012.ast.03

Manufacturer: Troughton & Simms, London

Date of Manufacture: Mid 1800s

Provenance:

University of Toronto Department of Astronomy

Donated to UTSIC: No

Historical Notes:

Old label: Ast 19, but not on UTMuSi website