Sextant

Astronomy

Accession Number: 2011.ast.1

Description:

Sextant, 2 telescope/optical attachments and clock winding key in fan shaped wooden storage box. Sextant is faded brass with wooden handle, angled with 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 140 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 can move along the graduated arc and has a movable viewing space marked from 0 to 10. One telescope attachment is short (12.9cm) and the other long (17.9cm), each have diameter 2cm. The key appears to be unrelated to the sextant and has a square shaped groove at the end. Engraved on the sextant measuring arm is “Rob’t. Deane Bombay”. Engraved on the graduated arc is “Troughton London”. The sextant and box additionally have a small blue label: “University of Toronto ASTRONOMY David Dunlop Observatory”.

Alternative Name:

Primary Materials:

Sextant and parts: Wood, brass, glass. Box: wood with some felt lining. Key: steel.

Markings:

“Troughton London” on graduated arc. “Rob’t. Deane Bombay” on measuring arm. “University of Toronto ASTRONOMY David Dunlop Observatory” on sextant and outside of box. Penciled on the inner lid of the box is “Miller 1925″.

Dimensions (cm): Length = 28, Width = 25.5, Height = 11

Function:

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

Condition:

Good. Brass? of sextant body is faded brown. Magnifying piece on measuring arm is slightly bent. Wooden box is in poor condition, hole on one side, bottom panel loose.

Associated Instruments: 2011.ast.02, 2011.ast.03

Manufacturer: Troughton, London

Date of Manufacture: Mid 1800s

Provenance:

Used by Astronomy Department. Acquired by Miller?

Donated to UTSIC: No

Historical Notes:

Also labelled as Ast 19, but not on old UTMuSi catalog.