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Bubble Sextant IX


This is a bubble sextant inside a brown box with a slanted lid. Two metal clips hold the lid shut. Attached the box there are three metal loops, to permit the box to be hung on a wall in two possible orientations. Also on the box there is a white plastic label, held in place by a metal frame. On either side there are the remnants of a leather strap, broken off at both ends near buckles that attach it to the box.

The instrument has become stuck inside the box, due to foam lining of the box that has decayed and adhere to the base of the instrument (as oriented in the box). The instrument is visibly similar in design and features to 2019.ast.153. The serial number of the box, which is blacked out, is different from the serial number on the instrument.

There are two “Eveready” brand batteries in the box and some cylindrical items again similar to 2019.ast.153.

Accession Number: 2019.ast.154

Alternative Name:

Primary Materials:

Wood Composite, Metal: Iron Alloy, Glass, Plastic (Foam)


On the box label: “6B.151
H. H. & S. LTD (V)

On a paper label attached to the box: “Ast 59-c”

Written in red marker or crayon on the box: “2”

Written in yellow crayon on the box: “6B/63

On the instrument: “SERIAL No. 4718/40 (V)”

Dimensions (cm):

Length = 23, Width = 20.3, Height = 18.6


The Bubble Sextant enables stellar navigation in situations where a standard sextant cannot be used as the horizon may not be level, as in an aircraft. The bubble creates an artificial horizon when the sextant is held correctly.


Poor: While the instrument appears to be in good or fair condition, it can no longer be removed from the box without excessive force. The instrument is worn across its surface, especially on edges, corners and around working aspects (e.g. dials and knobs).

The exterior of the box is scratched and marked, but intact.

Associated Instruments:


Henry Hughes & Son Ltd for the U.K. Air Ministry

Date of Manufacture: 1939-1945


The sextant was acquired by the Department of Astronomy or the David Dunlap Observatory sometime after 1945. This object was likely moved from the David Dunlap Observatory in Richmond Hill in 2008, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.

Additional Information and References:

Historical Notes: