McLaughlin Planetarium Building

The Planetarium Building

(The McLaughlin Planetarium was closed in 1995)

For some years there had been discussion in Toronto about the need for a major planetarium. One proposal, made in July, 1962, took the form of a bequest of $10,000 made by a former member of the Royal Astronomical Society of Canada. His intention was that the Society, either alone or in collaboration with the Royal Ontario Museum, should consider establishing a major planetarium in Toronto within ten years. In May, 1964, the President of the University of Toronto and the Chairman of its Board informed the National Council of the Royal Astronomical Society of Canada that it was enthusiastic about the idea of having a good planetarium connected with the Royal Ontario Museum. They added, however, that the necessary financial support would have to come from quarters other than those required to maintain the university’s large and urgent academic expansion program.

The project is launched

The necessary financial support came unexpectedly in November, 1964, when Colonel R. S. McLaughlin, in a telephone call to the Director of the Royal Ontario Museum, offered to donate approximately $1,000,000, a figure which he later increased to $2,000,000. Asked about his reason for the donation, Colonel McLaughlin answered: “Charlie Hayden was a great friend of mine. He was Chairman of the Board of Directors of International Nickel; I worked with him for several years and liked him very much. When he decided to have the Planetarium in New York built, I was very interested. My wife and I drove there when it was completed and I came back full of enthusiasm. At the time I had a few architects come along (this was more than 20 years ago) to find out what the chances were of erecting a Planetarium here.

“To our great disappointment, we could not get equipment here as it was not available anywhere in the world, and I, therefore, gave up the idea for the time being. When a few weeks ago my secretary brought me a newspaper cutting from a Toronto newspaper, where it was again mentioned that there was interest in building a Planetarium, I sent out a man to make enquiries. On his return, he indicated the equipment was now available in three countries. I telephoned the Director of the Museum and told him that if they would allow me to, I would like to have a Planetarium built for them. It would give me great pleasure to see it completed.

A month later a “users’ committee” under the chairmanship of the associate head of the Department of Astronomy, began to draw up detailed requirements for the project. One important result of its deliberations, combined with visits to other planetariums, was an outline proposal for the building. Stone and Webster Canada Limited, project managers and engineering consultants, in association with Allward and Gouinlock, consulting architects, then prepared the necessary detailed drawings and specifications. In December, 1966, the contract for the construction of the building was awarded to Milne and Nicolls Limited of Toronto, and work began on the site.

The Outer Dome

The MacLaughlin Planetarium stands on the site of an old house, at one time the residence of the President of the University of Toronto, at 86 Queen’s Park, directly south of the Royal Ontario Museum. Its most striking feature is the dome, which rises some 83 feet above the roadway, has an outer diameter of nearly 91 feet, and is built in layers like a sandwich. The inner or main shell is of reinforced concrete four to eight inches thick. This is overlain by a layer of foamed urethane and an outer shell of reinforced concrete 1 ½ inches thick. The outer shell is waterproofed with synthetic rubber material.

The building has two entrances for visitors – the main or street entrance, set back about 80 feet from the roadway, and a secondary, approached through the mineralogy gallery of the Royal Ontario Museum. Visitors who use the street entrance enter a main lobby or assembly area with its sales desk, coat room, and washrooms. Then they proceed by easy flights of stairs to large display areas (designed by Opus International Limited), and in so doing become gradually reoriented from earthly surroundings to objects in the depths of space. This psychological transition, encouraged by subdued lighting and the nature of the displays, is maintained right up to the entrance of the star theatre on the third floor.

The Projection Dome

The projection dome, just under 75 ½ feet in diameter, is physically independent of the outer dome. The space between them contains movable ladders (for gaining access to loudspeakers mounted directly behind the projection dome), and a gantry for reaching projectors and lights contained in the cove at the dome’s base.

The Projection dome was made by Astro-Tec Manufactured Incorporated of Ohio. It consists of carefully-shaped sheets of aluminium held in place by a framework of slender ribs. The sheets are lap-jointed to form a continuous surface accurately spherical to within 1/5 of an inch. At the close range, however, the surface is seen to be perforated with tiny holes at ¼ inch intervals. The holes are just under 1/10th of an inch in diameter and therefore are too small to interfere with even the smallest star images. Their function is to allow parts of sound waves to pass through the inner dome and be absorbed by sound insulation boards. This reduces the reflection of the waves and the formation of disturbing echoes. Finally, coats of special white paint are applied to the surface to ensure that it is a good reflector of light.

The millions of tiny holes in the projection dome also play an important part in the ventilation of the star theatre. Cool filtered air enters the theatre through the space between the outer and inner domes, and leaves through ducts at the base of the Zeiss projector. The coolness encourages the illusion of being outdoors on a clear, starry night, while the absence of dust particles ensures that light beams from the projectors to the dome remain invisible. Actually, the entire planetarium building is air conditioned, thereby creating a free, open feeling on even a warmest of days.

Every major planetarium should have a mechanical workshop to adequately maintain the moving parts of exhibits in the display areas and the optical projection assemblies. A workshop also is necessary for the development and construction of new exhibits and projectors. The McLaughlin planetarium has a large and well-equipped workshop on the first floor, directly below the spiral staircase in the north wing. There the technical staff can build almost any type of supplementary projector to ensure that the shows and lectures have the greatest possible interest, scope and variety.

Everything possible has been done to ensure that the McLaughlin Planetarium is one of the best of its kind in the world. Although a major planetarium, it is not by any means the largest, nor does it have, by reason of its location, an associated public observatory or observation deck. On the other hand it is a model of compactness – not a single square foot has been wasted – and represents an outcome of an immense amount of thought and planning. Its success will be measured not by its size, nor necessarily by the number of visitors who enter its doors in a year, but by the integrity with which it presents astronomy and the quality of its service to the community.