Menu Close

David Dunlap Observatory (DDO) Telescope Model


This object is a scale model of the 74-inch reflecting telescope at the David Dunlap Observatory at Richmond Hill, Ontario, which belonged to and was used by the University of Toronto from 1934 to 2008. The model is 1/30th the size of the real telescope. The most notable feature of the object is a scale model of the reflector telescope. This telescope is tube shaped, made of wood and painted grey in colour. The reflector telescope is articulated and rotates on an axis. The grey component at the base of the telescope may be for manipulation of the model, but may also represent the telescope’s Cassegrain spectroscope. This section of the mount is painted light blue with four screws painted orange. The entire model is attached to a wooden, rectangular base that is also painted a grey colour.

Accession Number: 2014.ast.24

Alternative Name:

Primary Materials: Metal: Iron Alloy, Wood


Dimensions (cm): Length = 38, Width = 16.5, Height = 24


The model was used for teaching purposes and conceptualizing instrumentation by the faculty and students in the Department of Astronomy and Astrophysics at the University of Toronto.


Fair. The wood base, which the model is mounted on, exhibits numerous hairline cracks in the layer of paint covering the entire surface. The paint is also flaking in various spots and there are dirt marks all over the base surface, edge and bottom. There is also a loss of wood along the right edge of the base. Near the mount of the telescope on the left side of the base surface there is a visible circular stain from a tool mark around a screw. The stain measures 1.3cm in diameters. The mount of the telescope is attached to the base however, there is a large rupture almost entirely separating the mount from the base. Screws have been placed inside the mount to fasten the piece to the base. It is unclear if these screws were installed during the objects original construction or added later. Along the front length of the mount there are tool markings where the object was filed/shaved during construction. The paint is flaking in various spots and there are dirt marks scattered over the mount. There is a 2-inch crack in the paint at the top of the side panel of the mount. There are a number of localized areas where the paint has cracked or is flaking all over the tube or reflecting telescope. Additionally, there is a loss along the tube as a piece of wood is missing. Inside the tube there appears to be some sort of infestation as there are insect webs visible down the tube.

Associated Instruments:


Possibly made by the machine shops in the basement of the observatory in the Department of Astronomy and Astrophysics at the University of Toronto or the David Dunlap Observatory..

Date of Manufacture: 1952-1953


This object was made at the David Dunlap Observatory in or just before 1953, and moved from there in in 2008, upon the sale of the observatory. It was stored at the Department of Astronomy and Astrophysics on U of T’s St George campus until 2017, when it was moved to a new storage location in McLennan Physical Laboratories.

Additional Information and References:

The object is currently in storage. It may have been previously displayed in the Astronomy and Astrophysics building, room 85 at the University of Toronto.

In 2013, the model was included in an exhibition titled, “Innovators in Instrumentation: Advancing Astronomy at the Dunlap Institute” curated by a group of graduate students from the Museum Studies program at the University of Toronto. This group of students included Samantha Haddon, Lauren Herzog, Emily Horne, Laura Imrie, Claire MacDonald-Matthews and Amanda McGee. “Innovators in Instrumentation” was intended to demonstrate the historical development of astronomical instrumentation over the past century. The exhibition opened to the public on March 22, 2013 on the 3rd floor of Victoria College on the downtown St. George campus at the University of Toronto. Visitors could view the exhibition Monday through Friday, 9am-5pm and admission was free. The exhibition ran until October, 2013.

David Dunlap Observatory (DDO): Document Instrumentation. 2006.

University of Toronto Events Calendar

Inventory List of “Innovators in Instrumentation: Advancing Astronomy at the Dunlap Institute” compiled by Samantha Haddon, Lauren Herzog, Emily Horne, Laura Imrie, Claire MacDonald-Matthews and Amanda McGee, 2013.

Views of the real telescope taken in September 2000 by U of T astronomer Don Fernie can be seen here: “David Dunlap Observatory (DDO) DDO Photos September 2000

Historical Notes:

This model, and the others like it, are described in the Dunlap Observatory’s 1953 update in the Notes from Observatories in the Journal of the Journal of the Royal Astronomical Society of Canada, Vol. 47, p.96: “A number of demonstration models depicting the largest telescopes in present use have been constructed in the shop of the David Dunlap Observatory. Built to the scale of one-quarter inch to the foot, these moving models were intended to demonstrate the advantages and drawbacks of the various methods of mounting an astronomical telescope. While primarily intended for the classroom, the models were displayed at the recent At-Home of the Royal Astronomical Society of Canada and at the Canadian Hobby and Homecraft show where they were viewed with lively interest. The limitations of a telescope mount or its ease of handling can be graphically demonstrated with models in a manner not possible with only diagrams and explanations.”
Professor Emeritus John Percy remembers them being useful later in the 20th century in the teaching of undergraduate students, particularly with regards to the operation of the David Dunlap Observatory’s 74” telescope itself:
“[B]ecause they were a more or less exact model they didn’t convey any misconceptions, and they gave you a way of visualizing how the telescope moved, how it could be pointed at different parts of the sky. You could certainly illustrate where the Newtonian focus was, and how difficult it was for Helen Hogg to access that [on the 74” telescope]. Whereas all the [other scientists] using it could conveniently [work] at floor level and so forth… And all three of the telescopes have a slightly different design for the mounting of it, to show there were different designs you could use and why you couldn’t use the same one for the 24-inch telescope, but you could for the 74-inch telescope.”
The models were mostly used on the downtown campus, where undergraduate classes were held.
John Percy was interviewed on March 11, 2021.