Category of Astronomical Heritage: tangible immovable
Dominion Astrophysical Observatory, Canada

Description

Geographical position

Dominion Astrophysical Observatory -- Observatoire fédéral d'astrophysique, 5071 West Saanich Road, Saanich near Victoria, British Columbia, V9E, Canada
(National Research Council Centre of the Universe -- Centre du conseil national de recherches de l'univers)
See also: NRC Herzberg Institute of Astrophysics

Location

Latitude 48°31'12'' N, Longitude 123°25'05'' W, Elevation 227m above mean sea level.

IAU observatory code

658

Description of (scientific/cultural/natural) heritage

Fig. 1a. The large Dome for the 1.85-m-Reflector, Neo-Renaissance portal of the Dominion Astrophysical Observatory, Victoria (*1918), (CC2, Robert Ashworth)

Fig. 1b. The large Dome of the Dominion Astrophysical Observatory, Victoria (*1918), (NHS Canada)

Architect Edgar Lewis Horwood (1868--1957), Chief Dominion Architect from 1915 to 1917, erected the Dominion Astrophysical Observatory, Victoria, British Columbia (1914 to 1918).

Victoria is located in the southwestern state of British Columbia on the southeastern tip of Vancouver Island, opposite of the coast of Washington State, USA. The Dominion Astrophysical Observatory (DAO), Victoria, is located on a hill 20 km away. The observatory's two-storey steel frame building, painted white with blue accents at the portal, has a cylindrical structure 20.2-m in diameter and 22.3-m high. On the top is the dome.

Fig. 2. John Stanley Plaskett (1865--1941), (CC)

The astronomer John Stanley Plaskett (1865--1941) chose this location instead of an initially planned location near Ottawa.
In addition, he disigned the later called 1.85-m-Plaskett Telescope, made by Brashear (1918). With this reflector Canada's astronomy got an international status.

The large domed building is "only" 20-m in diameter, and has double walls made of steel. The domed building is decorated with ornamentation in Neo-Renaissance style: the portal on the south side has a so-called adicula with a relief showing the Royal English coat of arms.

This famous Canadian observatory was in competition with the slightly older Mount Wilson Observatory, which had already a 1.5-m reflectinbg telescope. Plaskett continued the new developments in reflecting telescope technology during the early 20th century by constructing a reflecting telescope with 1.85-m aperture, made by the John A. Brashear company of Pittsburgh (1918). This was in development at the same time as the larger 2.5-m (100-inch) Hooker reflecting telescope (1917) of Mount Wilson Observatory.

In this world-renowned observatory many discoveries were made.
Plaskett was interested in radial velocities of stars (catalogue of "The radial velocities of 595 stars", 1922). In addition he discovered 200 spectroscopic binaries.
A highlight of Plaskett's discoveries was in 1922: a binary system which had the greatest mass of any then known.
In collaboration with Joseph Algernon Pearce (1893--1988), Plaskett confirmed the rotation rate of our Milky Way Galaxy (1928 to 1935).

The "Plaskett telescope" remained the second largest in the world until 1935, when the 1.88-m (74-inch) reflector at David Dunlap Observatory (DDO), Toronto, Canada, was constructed.

It was only 40 years later that the observatory received a second large instrument, a reflector with a 1.2-m aperture.

Since 1995, the DAO functions as the headquarters of the National Research Council of Canada (NRC) Herzberg Institute of Astrophysics.

History

Fig. 3a. 1.85-m-Reflector of the Dominion Astrophysical Observatory, Victoria (*1918), (DAO)

Fig. 3b. Plaskett-telescope of the Dominion Astrophysical Observatory, Victoria (*1918), (CC)

Fig. 3c. 1.85-m-Reflector (72-inch) of the Dominion Astrophysical Observatory, Victoria (*1918), (DAO)

Instruments of the Dominion Astrophysical Observatory, Victoria

12-inch Newton Reflector
1.85-m (72-inch) Reflecting telescope (Plaskett Telescope),
1.85-m (72-inch) glass mirror, 12 inches (0.30m) thick, weight approximately 1.97 t,
made by the Saint-Gobain company, Charleroi glass works of Antwerp, Belgium,
grinded and polished by the John A. Brashear of Pittsburgh, Pennsylvania (1918),
mounting by Warner & Swasey of Cleveland, Ohio,
with a stellar spectrograph with one or three prisms in the Cassegrain focus, CCD in the Newtonian focus
1.22-m (48-inch) Reflecting telescope, made by Grubb Parsons of Newcastle-upon-Tyne (1957--1962)
with a high resolution McKellar room-sized spectrograph in the Coudé focus,
used to study binary stars.
...

Fig. 4. John Stanley Plaskett (1865--1941), (CC)

Directors of the Dominion Astrophysical Observatory, Victoria

1918 to 1935 -- John Stanley Plaskett (1865--1941),
Research Astronomer: William Edmund Harper (1878--1940),
Astronomers: Reynold Kenneth Young (1886--1973), Harry Hemley Plaskett (1893--1980)
1940 to 1951 -- Joseph Algernon Pearce (1893--1988),
1935 to 1940 Assistant Director
...
...
1977 to 2014 -- James (Jim) Hesser, Emeritus

State of preservation

National Historic Site of Canada:
Historic Sites and Monuments Act (R.S.C., 1985, c. H-4)
An observatory clad in painted white metal panels and featuring classically inspired architectural embellishments; it is a world-renowned facility where many discoveries about the nature of the Milky Way were made, and it was one of the world's main astrophysical research centres until the 1960s.
(Canadian Register of Historic Places, recognition date: 2010/01/12.)

Fig. 5a. General view of Dominion Astrophysical Observatory (1918) showing its simple cylindrical massing topped by a domed roof, Parks Canada Agency/Agence Parcs Canada, Andrew Waldron, 2008 (NHS Canada)

Fig. 5b. Dominion Astrophysical Observatory, 1974, embedded in the landscape (CC4, Miranda Kopetzky)

Comparison with related/similar sites

It started as a one dome observatory. Now it is an astronomy park on a hill.

Threats or potential threats

no threats

Present use

The Dominion Astrophysical Observatory, Victoria, offers - in addition to the research activities - "The Centre of the Universe of the Dominion Astrophysical Observatory" for public outreach, opened in 2002. In 2014, the non-profit charity Friends of the Dominion Astrophysical Observatory (registered in 2015) runs the education programmes.

Astronomical relevance today

The Dominion Astrophysical Observatory, Victoria, is still an observatory of outstanding research.

The NRC Herzberg Institute of Astrophysics operates several Canadian telescopes like the Canada-France-Hawaii Telescope at Maunakea, Hawai'i (1979), and radiotelescopes.

References

Bibliography (books and published articles)

Broughton, R. Peter: Northern Star: J.S. Plaskett. With a foreword by James E. Hesser. Toronto: University of Toronto Press 2018.
Hodgson, John: The History of the Dominion Observatories: I 1905--1946; II 1946 -- the present. Ottawa 1965.
Plaskett, John Stanley: The Dominion Astrophysical Observatory, Victoria, B.C.; a sketch of the development of astronomy in Canada and of the founding of this observatory. a description of the building and of the mechanical and optical details of the telescope. An account of the principal work of the institution. Ottawa: F.A. Acland 1923 (https://archive.org/details/dominionastrophy00domiuoft).