The Dominion Astrophysical Observatory was inaugurated in 1918 at Saanich near Victoria, British Columbia. Its creation was motivated by the growing need of Canadian astronomers to have access to a large world-class telescope. The observatory immediately achieved international status by housing a 1.83-metre telescope that was the largest operating telescope in the world, although it only held this title for a few months.

The installation of the telescope was largely the work of celebrated Canadian astronomer John Stanley Plaskett, and the instrument was baptized the “Plaskett Telescope” in his honour. It measured 15 metres long and its mobile parts weighed 42 tonnes.

Plaskett became the first Director of the Dominion Astrophysical Observatory and helped it establish an international research reputation very early on. In 1922, for example, he discovered a binary star and the larger of the two still holds the record as the most massive known binary star. This celestial body bears the name of “Plaskett’s Star” in his honour.

During subsequent years, Plaskett established the radial velocities of several stars (that is, the Read More
The Dominion Astrophysical Observatory was inaugurated in 1918 at Saanich near Victoria, British Columbia. Its creation was motivated by the growing need of Canadian astronomers to have access to a large world-class telescope. The observatory immediately achieved international status by housing a 1.83-metre telescope that was the largest operating telescope in the world, although it only held this title for a few months.

The installation of the telescope was largely the work of celebrated Canadian astronomer John Stanley Plaskett, and the instrument was baptized the “Plaskett Telescope” in his honour. It measured 15 metres long and its mobile parts weighed 42 tonnes.

Plaskett became the first Director of the Dominion Astrophysical Observatory and helped it establish an international research reputation very early on. In 1922, for example, he discovered a binary star and the larger of the two still holds the record as the most massive known binary star. This celestial body bears the name of “Plaskett’s Star” in his honour.

During subsequent years, Plaskett established the radial velocities of several stars (that is, the speed at which the stars are moving away or toward the observer) and demonstrated that our galaxy, the Milky Way, is rotating. He was also the first to measure the size, mass and rotational The 1.83-metre Plaskett Telescope of the Dominion Astrophysical Observatory.speed of the Milky Way. He also established that the Sun is located at 2/3 the distance from the centre of our galaxy to its edge, and that our solar system takes approximately 22 million years to complete one galaxial rotation.

In 1940, the Dominion Astrophysical Observatory was the site of two other major discoveries. Andrew McKellar, one of the observatory’s astronomers, became the first researcher to detect the presence of matter in interstellar space when he identified the spectral bands for the organic compounds cyanogen (“CN”) and methyne (“CH”). One year later, in 1941, he determined the temperature of the cyanogen molecules and deduced that the interstellar environment in which they are found is very cold, approximately -270 °C. It was the first direct measurement of the temperature of the Universe.

In 1962, the observatory acquired a second telescope measuring 1.22 metres in diameter. Equipped with only a spectroscope, it was mainly used to study binary stars.

In 1970, the responsibility of the observatory was conferred to the National Research Council of Canada.

In 1981, the observatory received a third telescope measuring 40 centimetres across. It was primarily used for scientific research, notably the study of gas clouds in our galaxy (the Milky Way), and to test instruments destined for large telescopes. Today it is used to show the sky to the general public.

In 1995, the observatory became the headquarters for the Herzberg Institute of Astrophysics, which operates several telescopes (optical and radio) in Canada and shares many others with various countries elsewhere in the world, including the Canada-France-Hawaii Telescope and the Gemini telescopes.

In 2001, the observatory inaugurated an interpretation centre open to the general public all year long and affectionately named “The Centre of the Universe”. It includes a small planetarium and offers interactive displays, multimedia presentations and special events designed to introduce people from all walks of life to the world of astronomy.

Over the years, new instruments were added and many technical improvements were made to the Plaskett Telescope, the observatory’s main telescope. Today, the Dominion Astrophysical Observatory is the responsibility of the National Research Council of Canada’s Herzberg Institute of Astrophysics.

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour photo of the Dominion Astrophysical Observatory

The Dominion Astrophysical Observatory.

National Research Council of Canada

© National Research Council of Canada


Colour photo of the Plaskett Telescope in the dome with the door open

The 1.83-metre Plaskett Telescope of the Dominion Astrophysical Observatory.

National Research Council of Canada

© National Research Council of Canada


Black and white photo of McKellar Telescope

The 1.22-metre McKellar Telescope of the Dominion Astrophysical Observatory.

National Research Council of Canada

© National Research Council of Canada


The Dominion Radio Astrophysical Observatory was inaugurated in 1960 at White Lake near Penticton, British Columbia. The creation of the observatory was primarily the work of Carlyle Smith Beals, an astronomer who wanted to advance the field of astrophysics in Canada.

The first parabolic antenna, measuring 25.6 metres, began operating in 1960. It was mainly designed to operate at a wavelength of 21 centimetres, which corresponds to one of the spectral lines of hydrogen.

The study of hydrogen is of great importance to astronomers: hydrogen is the most abundant chemical element in the Universe, where it is present as a gas, and studying its distribution in the Milky Way can help astronomers reveal the structure of our galaxy. Radio astronomers at Penticton have been striving towards this goal since the first days of the observatory.

Cedar postsIn 1962, a second radio telescope was put in place. Fully operational in 1964, it consisted of 1,700 cedar posts that extended for 1.3 kilometres in the shape of a “T” to cover a surface area of 65,000 square metres. The posts supported a network of several thousand metres of metallic wires formed t Read More
The Dominion Radio Astrophysical Observatory was inaugurated in 1960 at White Lake near Penticton, British Columbia. The creation of the observatory was primarily the work of Carlyle Smith Beals, an astronomer who wanted to advance the field of astrophysics in Canada.

The first parabolic antenna, measuring 25.6 metres, began operating in 1960. It was mainly designed to operate at a wavelength of 21 centimetres, which corresponds to one of the spectral lines of hydrogen.

The study of hydrogen is of great importance to astronomers: hydrogen is the most abundant chemical element in the Universe, where it is present as a gas, and studying its distribution in the Milky Way can help astronomers reveal the structure of our galaxy. Radio astronomers at Penticton have been striving towards this goal since the first days of the observatory.

Cedar postsIn 1962, a second radio telescope was put in place. Fully operational in 1964, it consisted of 1,700 cedar posts that extended for 1.3 kilometres in the shape of a “T” to cover a surface area of 65,000 square metres. The posts supported a network of several thousand metres of metallic wires formed the antenna of the radio telescope.

This radio telescope was primarily used between 1965 and 1969 during a period when solar spots were at a minimum. In fact, it is only during these periods of low solar activity that very long radio waves from space can pass through the atmosphere to reach Earth’s surface.

The Dominion Radio Astrophysical ObservatoryThe main goal of the T-shaped radio telescope at Penticton was to produce a map of radio sources in our galaxy. It was also used to observe several hundred specific radio sources, such as quasars and distant galaxies.

In 1965, a 1.8-metre parabolic antenna was installed to collect data on solar radiation. The radio telescope operated at a wavelength of 11.1 centimetres and its goal was to complement the data already gathered by the Algonquin Radio Observatory at Traverse Lake in Ontario.

In 1968, the 25.6-metre radio telescope at Penticton was used in conjunction with the 46-metre telescope at the Algonquin Radio Observatory to simulate the resolution of a giant radio telescope measuring 3,074 kilometres (the physical distance between the two instruments). It was the first successful long distance interferometry experiment ever conducted.

AntennasEncouraged by the results, the Dominion Radio Astrophysical Observatory commenced the construction of a synthesis radio telescope near the end of the 1960’s. It consisted of two parabolic radio telescopes measuring 8.5 metres across that would operate together to simulate a larger radio telescope with a 600-metre diameter. The antennas would operate at a wavelength of 21 centimetres, which corresponds to one of the spectral lines of hydrogen.

Today, the synthesis array radio telescope consists of seven 8.5-metre parabolic antennas that can operate continuously, 24 hours a day, at two wavelengths (21 and 74 centimetres). From 1995 to 2005, the radio telescope was mainly used in the Canadian Synthesis radio telescopeGalactic Plane Survey, the goal of which is to map a large portion of the Milky Way.

In 1990, following the closure of the Algonquin Radio Observatory, the task of gathering data on the Sun’s radio flux (the variations in its energy output at radio wavelengths) was transferred to the Dominion Radio Astrophysical Observatory at Penticton.

The observatory is now under the responsibility of the National Research Council of Canada’s Herzberg Institute of Astrophysics.

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour photo of the 25.6-metre Parabolic Antenna

The 25.6-metre parabolic antenna.

National Research Council of Canada
Herzberg Institute of Astrophysics/Dominion Radio Astrophysical Observatory

© National Research Council of Canada


Colour photo of Radio Telescope

The 1,700 cedar posts of the 1.3-kilometre radio telescope.

National Research Council of Canada
Herzberg Institute of Astrophysics/Dominion Radio Astrophysical Observatory

© National Research Council of Canada


Colour photo of the Dominion Radio Astrophysical Observatory

The Dominion Radio Astrophysical Observatory.

National Research Council of Canada
Herzberg Institute of Astrophysics/Dominion Radio Astrophysical Observatory

© National Research Council of Canada


Colour Photo of the Seven Parabolic Antennas

The seven 8.5-metre parabolic antennas of the synthesis radio telescope.

National Research Council of Canada
Herzberg Institute of Astrophysics/Dominion Radio Astrophysical Observatory

© National Research Council of Canada


Colour photo of Antennas in dry landscape

Antennas used to collect solar flux data.

National Research Council of Canada
Herzberg Institute of Astrophysics/Dominion Radio Astrophysical Observatory

© National Research Council of Canada


The University of British-Columbia Liquid-Mirror Observatory was established in 1995 at Maple Ridge, approximately 60 kilometres east of Vancouver. The goal of the observatory is to develop and test new liquid mirror telescopes. Liquid mirror telescopes are part of the next generation of super telescopes.

A liquid mirror is made of a strongly reflective liquid (like mercury, for example) that rotates so that its surface curves and takes the shape of a paraboloid, which will direct and concentrate light to the focal point of a telescope. This type of mirror has a major advantage over conventional mirrors in that it is much cheaper to build (up to 100 times less expensive).

In 1982, Ermanno Franco Borra, a professor in the Physics Department at Laval University in Quebec, revived the historical proposal of creating liquid mirror telescopes and sought to demonstrate the feasibility of such a project. Several liquid mirrors were subsequently developed at Laval University in the 1980’s.

In 1994, Paul Hickson of the University of British-Columbia completed the construction of the first liquid mirror telescope in collaboration with Borra. The mirror Read More
The University of British-Columbia Liquid-Mirror Observatory was established in 1995 at Maple Ridge, approximately 60 kilometres east of Vancouver. The goal of the observatory is to develop and test new liquid mirror telescopes. Liquid mirror telescopes are part of the next generation of super telescopes.

A liquid mirror is made of a strongly reflective liquid (like mercury, for example) that rotates so that its surface curves and takes the shape of a paraboloid, which will direct and concentrate light to the focal point of a telescope. This type of mirror has a major advantage over conventional mirrors in that it is much cheaper to build (up to 100 times less expensive).

In 1982, Ermanno Franco Borra, a professor in the Physics Department at Laval University in Quebec, revived the historical proposal of creating liquid mirror telescopes and sought to demonstrate the feasibility of such a project. Several liquid mirrors were subsequently developed at Laval University in the 1980’s.

In 1994, Paul Hickson of the University of British-Columbia completed the construction of the first liquid mirror telescope in collaboration with Borra. The mirror measured 2.64 metres in diameter.

The Large Zenith Telescope.The following year, Hickson installed his telescope in the newly inaugurated University of British-Columbia Liquid-Mirror Observatory. In order to test it, the liquid mirror examined galaxies along a strip of deep sky, and the results were conclusive giving the green light to a new series of experiments that would lead to the construction of a bigger and more powerful liquid mirror.

The efforts of Hickson and his collaborators culminated in 2004 when the 6-metre liquid mirror Large Zenith Telescope went into operation. The name Zenith is derived from the fact that the telescope always observes the zenith – that is, directly overhead – because the liquid mirror cannot be tilted (the mercury would fall out of the dish).

The Large Zenith Telescope is the third largest optical telescope in North America and the largest liquid mirror telescope in the world. Despite its enormous size, the mirror components weigh only 3 tonnes.

At the present time, the observatory is involved in two large-scale projects. The first is the construction of the ALPACA telescope (Advanced Liquid-mirror Probe for Astrophysics, Cosmology and Asteroids), which consists of a liquid mirror measuring 8 metres in diameter.

The second project is LAMA (Large Aperture Mirror Array), which consists of an array of 66 liquid mirror telescopes each measuring 6.15 metres in diameter. The array will simulate a telescope measuring 50 metres in diameter.

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour photo of the exterior of the University of British-Columbia Liquid-Mirror Observatory

The University of British-Columbia Liquid-Mirror Observatory.

The University of British-Columbia Liquid-Mirror Observatory

© The University of British-Columbia Liquid-Mirror Observatory


Colour photo of the Large Zenith Telescope

The Large Zenith Telescope.

The University of British-Columbia Liquid-Mirror Observatory

© The University of British-Columbia Liquid-Mirror Observatory


The Rothney Astrophysical Observatory was inaugurated in 1972 at Priddis, a small locality 75 kilometres southwest of Calgary, Alberta. Belonging to the University of Calgary, the facility was operated by the astronomy and physics departments. The objectives the observatory were the advanced education of university students and the pursuit of astronomical research.

The history of the observatory began in 1967 when the physics department at the University of Calgary developed a graduate program in astrophysics, and the department soon decided to create an astronomical observatory for its students and researchers.

In 1970, Alexander Rothney Cross, a wealthy rancher, donated land to the University of Calgary for the purpose of constructing the observatory. Work commenced in 1971 and the university took the opportunity to simultaneously start an undergraduate degree in astronomy. The observatory opened its doors in 1972 to display a dome housing a 41-centimetre telescope, and an adjacent lecture room. The first research activities were mostly on photometry.

The year of 1981 was particularly fruitful for the observatory. The National Research Council of Read More
The Rothney Astrophysical Observatory was inaugurated in 1972 at Priddis, a small locality 75 kilometres southwest of Calgary, Alberta. Belonging to the University of Calgary, the facility was operated by the astronomy and physics departments. The objectives the observatory were the advanced education of university students and the pursuit of astronomical research.

The history of the observatory began in 1967 when the physics department at the University of Calgary developed a graduate program in astrophysics, and the department soon decided to create an astronomical observatory for its students and researchers.

In 1970, Alexander Rothney Cross, a wealthy rancher, donated land to the University of Calgary for the purpose of constructing the observatory. Work commenced in 1971 and the university took the opportunity to simultaneously start an undergraduate degree in astronomy. The observatory opened its doors in 1972 to display a dome housing a 41-centimetre telescope, and an adjacent lecture room. The first research activities were mostly on photometry.

The year of 1981 was particularly fruitful for the observatory. The National Research Council of Canada decided to finance the construction of a new facility that would house a 1.5-metre telescope capable of operating in the infrared range. Alexander Rothney Cross signed on to the project by making another donation. The Canadian Forces Base Cold Lake also provided a gift: a Baker-Nunn camera that the Armed Forces had used to track satellites in the sky.

The new facility was constructed by the physics department of the University of Calgary. Construction continued for several years and by 1987 the 1.5-metre telescope was operational. The physics department changed its name to the Department of Physics and Astronomy.

The 1.8-metre telescope of the Rothney Observatory.Most of the research work focused on the study of stars, X-ray sources, possible black holes and planetary nebulas. The telescope was still equipped with a metal mirror (not glass), and its optical qualities were considered less than optimal by that time. The decision was made at the end of the 1980’s to replace it with a new 1.8-metre mirror.

The new mirror was delivered to the observatory in 1993, and once again, Alexander Rothney Cross contributed to the project. Construction was completed by the workshop of the Department of Physics and Astronomy, and the telescope became operational in 1996. The following year, it was baptized as the Alexander Rothney Cross Telescope in honour of the generous benefactor.

The new telescope is used to observe (among other things) gravitational lenses, asteroids, comets and variable stars, and is also used in the search for planets outside our solar system.

Recent developments include a new Visitor’s Centre that was inaugurated in 2003. The 41-centimetre telescope continues to be operational and is used to track asteroids that orbit near Earth and represent a possible danger.

© 2006 An original idea and a realization of the ASTROLab of Mont-Mégantic National Park

Colour photo of the exterior of the Rothney Astrophysical Observatory

The Rothney Astrophysical Observatory.

The Rothney Astrophysical Observatory

© The Rothney Astrophysical Observatory


Colour photo of the Telescope of the Rothney Observatory

The 1.8-metre telescope of the Rothney Observatory.

The Rothney Astrophysical Observatory

© The Rothney Astrophysical Observatory


Learning Objectives

The learner will:
  • identify recent contributions, including Canada’s, to the development of space exploration technologies;
  • describe in detail the function of Canadian technologies involved in exploration of space;
  • draw a solar system with all its components;
  • establish the link between atoms and light using different instruments.

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