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Floating Gnomon Pocket Sundial


This instrument is a small instrument in a wooden case with a domed lid. The case is cylindrical and separates into a base and a top that can be completely removed. Underneath the lid there is a glass dome cover covering the sundial. The dial consists of a circular central flat disk that freely rotates and orients itself like a compass. On top of this, sitting vertically there is a triangular metal piece, and around this lines indicating hours. These are labelled around the rim with Roman numerals, except for the line aligned with the orientation of the triangular section, which is labelled “S”.

Around the edge of this rotating section there is a fixed rim decorated with a painted floral pattern. This is labelled: “OST” “SUD” “WEST” “NORD”.

There is a white paper label with a petal shape affixed to the base of the instrument.

Accession Number: 2019.ast.258

Alternative Name:

Pantochronometer, Magnetic Dial Sundial, Pocket Sundial, Pocket Compass, Pocket Sundial/Compass

Primary Materials: Wood, Glass, Paper, Metal: Iron Alloy


Around the rim of the sundial: “OST” “SUD” “WEST” “NORD”

On the white label on the base: “48”

Written in black ink on the base, and obscured by the label: “1 # 10”

Dimensions (cm):


This instrument was designed to permit the user to tell the time by shadows cast by the sun, using a magnetic dial to correctly orient the gnomon north-south. As sundial are oriented to true, rather than magnetic, north, this dial would become inaccurate over time as magnetic north shifted. It was likely sold as a novelty item, never intended to be very accurate.


Very Good: Aside from the label and writing on the base, the wooden base of the instrument is in good condition; however, the lid has two serious cracks running against the wooden grain and a chunk of the edge of the side missing. The dome of the sundial is intact, although there is some residue around the base. The interior of the dial appears to be in good condition.

Associated Instruments:


Johann Paul Stockert (Bavaria), or David Beringer (Nuremberg) Germany

Date of Manufacture: c.1790 – 1810


This instrument was acquired as an antique by Reynold K. Young, former Director of the David Dunlap Observatory (1935-1946), likely as a display object. Since, it has been either on display at the department or in storage at the David Dunlap Observatory in Richmond Hill, or at the Department of Astronomy and Astrophysics building on the St. George Campus at the University of Toronto.

Additional Information and References:

Information about a sundial similar to this one can be found at<a href=></a>

Historical Notes: