Sundial Casting Mold

Astronomy

Accession Number: 2019.ast.147.1-2 (DDA-0108)

Description:

The main part of this object (2019.ast.147.1) consists of a rectangular piece of wood carved on one surface into a sundial pattern. This is painted with a copper-coloured metallic paint and has a metallic inset along one edge. The sundial pattern has a four-pointed star in the centre, with W, N and E marked. Around three edges of the sundial there are numerals from 12 (at the N mark) counting from 11 to 5 on one side, and up from 1 to 7 on the other, like the standard arrangement of a clock face. On the S side of the sundial the metal insert gives instructions “To Get Standard Time Add to Dial Time The Number of Minutes Given Below” and provides a chart for reference which is given in months.

Accompanying this is a piece of wood used to create an indicating arm for a sundial (2019.ast.147.2)

Primary Materials: Wood, Metal: Copper Alloy?

Markings:

On the metal insert: “TO GET STANDARD TIME ADD TO DIAL TIME THE NUMBER OF MINUTES GIVEN BELOW”

Dimensions (cm):

Length = 30.5, Width = 30.5, Height = 2.8

Function:

This is a casting mold pattern to make metallic casts of sundials. Sundials permit the use of the sun’s angle in the sky to tell the approximate time.

This information is given in the Astronomy catalogue: “This design for the sundial on the grounds of the observatory was fashioned in wood by a skilled patternmaker. To make the sundial, the pattern was placed in a mould box (flask), and casting sand was packed around it. When the pattern was removed, it left its precise impression in the casting sand to form the mould. Molten metal was then poured into the mould to cast the sundial. Many of the mechanical parts of both the 74-inch and 19-inch telescopes were made in the same way. Unlike telescopes, sundials are millennia-old in conception, and while long obsolete for research, they nevertheless found a place in the decorative scheme of observatories. Sundials symbolically represented the claim to a long cultural preoccupation with astronomy, to which the latest equipment is the culmination.”

Condition:

Very good: The wood surface is in good condition, although the metallic paint does not cover the whole surfaces. Around all four edges, the copper-coloured painted has oxidized to a blue-green colour. The cast is dirty and marked in places, likely from use. The wood is in overall good condition with no chips or cracks.

Associated Instruments: 2019.ast.148

Manufacturer: Locally made

Date of Manufacture: c. 1935

Provenance:

This casting mold was created for use at the David Dunlap Observatory, likely during or upon its construction (1935). Upon the sale of the observatory in 2009 it was moved, along with the other items in this collection, to the Department of Astronomy and Astrophysics building at the St George Campus at the University of Toronto. It was stored there until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.