Algonquin Radio Observatory
Encyclopedia
The Algonquin Radio Observatory (ARO) is a radio telescope
research
facility located in the Algonquin Provincial Park
in Ontario
, Canada
. The site's primary instrument is a major 46 m (150 ft) parabolic-dish radio antenna. This instrument is historically famous for taking part in the first successful very long baseline interferometry
experiment in the 1960s. The site also formerly ran a solar
-observing array of thirty-two 10 ft (3 m) dishes, and a single 1.8 m solar flux monitor observing at 10.7 cm wavelength. The site is currently used to provide high accuracy geodetic location information to the present day for applications such as real time GPS signal correction.
Laboratory, 10 m (32.8 ft) dish and parabolic microwave feed horn instruments were designed in 1959 and construction was completed in phases over the next several years. In 1961, the site was selected by the National Research Council of Canada
as suitable for the construction of a 120 ft (36.6 m) fully steerable antenna. By 1962, plans showed that the main instrument had grown to a 150 ft (45.7 m) antenna; construction of this commenced in 1964.
had been running a solar observation program at the National Research Council of Canada
(NRC) Ottawa Radio Field Station. The station was primarily a radar
research site, and ongoing radar work interfered with the solar instrument Covington had built as a personal project. As the value of the observations became evident, the instrument was moved about five miles (8 km) away to Goth Hill, a more radio-quiet location. But as Ottawa grew this site soon started becoming radio-noisy as well, due mostly to increasing air traffic at a nearby airport. Looking to improve the quality of their measurements, they proposed building a new solar telescope located far away from built up areas. Easy access from Ottawa
made Algonquin a fairly obvious choice, although it was about 200 km away the roads were good quality and easy to travel.
Construction of the solar observation site started in 1959. The first instrument on the site was a new solar telescope, similar to Covington's original 4 ft (1.2 m) instrument, but slightly enlarged to 6 ft (1.8 m) which allowed it to better observe the entire solar disk. This instrument operated in parallel to the original at Goth Hill until 1962, when it took over these duties completely. A second 6 ft (1.8 m) telescope, identical to the one at ARO, was later installed at the Dominion Radio Astrophysical Observatory
(DRAO) in Penticton, British Columbia
as a backup.
Another solar instrument pattered on a different Goth Hill device followed, this one consisting of a series of thirty-two 10 ft (3 m) parabolic collectors connected to a common 700 ft (215 m) long waveguide
. Using phased array
techniques this instrument could image portions of the Sun's disk, compared to the single-dish instrument which saw the sun as a single unresolved "dot". The new instrument was up and running in 1966, adding to Covington's study of the sun by directly imaging the radio signal from sunspots and filaments.
in the base, only five feet high, positioned the instrument. The telescope was designed to operate at higher frequencies than existing instruments, requiring much of it to be constructed of flat plates instead of an open mesh in order to accurately focus these signals. The surface was built to be accurate to 1/5 of a centimeter, allowing it to accurately focus wavelengths to around 1.5 cm. Construction was completed in early 1966, and the telescope started operations in May 1966. Work was also completed a polar mounted paraboloid microwave horn and an 11 m equatorial mount dish north of the main antenna complex.
One of the earliest extended projects carried out on the instrument was the first successful very long baseline interferometry
(VLBI) experiment. Long Baseline Interferometry compares the signals from two or more telescopes, using the differences in phase between the signals to resolve the objects. Earlier experiments had used direct electrical links or microwave relays to extend the distance between the two telescopes, while still allowing real-time comparison of the phase of the two signals in a common instrument. However this limited the distance between the two instruments, to the distance the signal could travel while still remaining in-phase. The NRC invented a new technique that eliminated the need to directly compare the signals in real-time. Their technique used 2 inch Quadruplex videotape
to record the signals along with a clock signal from an atomic clock
. The clock signal allowed the two signals to be later compared with the same accuracy that had formerly required direct realtime connections. NRC funded the installation of identical instruments at the ARO and a smaller telescope at DRAO. Combining the signals would simulated a single 3,074 km diameter radio telescope.
Having learned that the Americans were also attempting a similar VLBI experiment, they tried to be the first to successfully use the technique. Their target for the experiment was quasar
3C 273. Recordings were made into the early morning of April 17, 1967. DRAOs tapes and atomic clock were shipped to the ARO for comparison, and after a month of trying to get the data to "line up", on May 21 they succeeded. After a few more days they had made the first highly accurate measurement of the size of the quasar, showing it was less than 100 light years across, about 1/1000 the span of the Milky Way
. Further experiments revealed the fact that 3C 273 had a distinct "jet".
In 1968 the 150 ft (45.7 m) telescope was used in a geodesy
experiment that measured the distance between the ARO and space-tracking telescopes in Prince Albert, Saskatchewan
to 2143 km +/- 20 m. Other early experiments included a study of flare star
s by Queen's University
. It was also used by Alan Bridle and Paul Feldman in 1974 for the first SETI
search to be carried out at the 1.35 cm wavelength, emitted by water molecules in space.
, which would include a radio telescope that could operate at 0.3 to 2 mm.
In 1988 the NRC invited the operators of the Hay River Radio Observatory in the Northwest Territories
, the Interstellar Electromagnetics Institute (IEI), to relocate their SETI
efforts to ARO. Due to budget cuts the NRC had been unable to use the ARO for research for some time, and were looking for low-cost projects that might be able to make use of the equipment. IEI jumped at the chance, and operated a SETI effort known as Project TARGET on the 18 m UofT telescope until 1991, when continuing budget cuts forced the NRC to cease operation of the site.
The continuing solar measurements, now used worldwide to predict communications problems due to sunspot
activity, were turned over to DRAO. At first the DRAO instrument was made "prime", and then once operation was demonstrated, the original Ottawa instrument was moved to join it as a hot backup
.
The University of Toronto
also operated their own 18 m telescope at the ARO for some time, after having moved it from the David Dunlap Observatory
which proved to be too close to the growing Toronto
area. The smaller University of Toronto antenna and the 32-dish solar observatory were both donated to project TARGET, and have since been relocated to a new site near Shelburne, Ontario
.
The main ARO telescope was later operated by Natural Resources Canada
and the Space Geodynamics Laboratory, CRESTech, who used the telescope in VLBI projects to measure the movements of continental plates in geodetic surveys. They have made several upgrades to the main 150 ft (45.7 m) telescope after taking over operations, allowing it to track at higher speeds necessary to track satellite
s.
The telescope was used in ongoing VLBI experiments carried out by a worldwide consortium supported by the HALCA
satellite, producing a 30,000 km-baseline telescope. The system is driven by the S2 software developed at York University
.
services utilizing the 46 m antenna. The site is an active control point for the global positioning system
. The main antenna is equipped with receivers for the detection of L-band, S-band and X-band. The observatory's hydrogen maser
maintains time standard stability to one part in 1015 in order to facilitate VLBI activities. By appointment ARO is open to visitors. Thoth also provides access to the site for activities such as York University
's space engineering field schools and research programs. For further information visit Algonquin Radio Observatory's official website.
Radio telescope
A radio telescope is a form of directional radio antenna used in radio astronomy. The same types of antennas are also used in tracking and collecting data from satellites and space probes...
research
Research
Research can be defined as the scientific search for knowledge, or as any systematic investigation, to establish novel facts, solve new or existing problems, prove new ideas, or develop new theories, usually using a scientific method...
facility located in the Algonquin Provincial Park
Algonquin Provincial Park
Algonquin Provincial Park is a provincial park located between Georgian Bay and the Ottawa River in Central Ontario, Canada, mostly within the Unorganized South Part of Nipissing District. Established in 1893, it is the oldest provincial park in Canada. Additions since its creation have increased...
in Ontario
Ontario
Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
, Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. The site's primary instrument is a major 46 m (150 ft) parabolic-dish radio antenna. This instrument is historically famous for taking part in the first successful very long baseline interferometry
Very Long Baseline Interferometry
Very Long Baseline Interferometry is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.Data...
experiment in the 1960s. The site also formerly ran a solar
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
-observing array of thirty-two 10 ft (3 m) dishes, and a single 1.8 m solar flux monitor observing at 10.7 cm wavelength. The site is currently used to provide high accuracy geodetic location information to the present day for applications such as real time GPS signal correction.
The Observatory
Algonquin Radio Observatory was inaugurated in 1959 and became Canada's national radio observatory in 1962. The observatory house complex, radiometer building, utility buildings, University of TorontoUniversity of Toronto
The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...
Laboratory, 10 m (32.8 ft) dish and parabolic microwave feed horn instruments were designed in 1959 and construction was completed in phases over the next several years. In 1961, the site was selected by the National Research Council of Canada
National Research Council of Canada
The National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
as suitable for the construction of a 120 ft (36.6 m) fully steerable antenna. By 1962, plans showed that the main instrument had grown to a 150 ft (45.7 m) antenna; construction of this commenced in 1964.
Solar observations
Prior to the construction of the ARO, Arthur CovingtonArthur Covington
Arthur Edwin Covington is a Canadian physicist who made the first radio astronomy measurements in Canada...
had been running a solar observation program at the National Research Council of Canada
National Research Council of Canada
The National Research Council is an agency of the Government of Canada which conducts scientific research and development.- History :...
(NRC) Ottawa Radio Field Station. The station was primarily a radar
Radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
research site, and ongoing radar work interfered with the solar instrument Covington had built as a personal project. As the value of the observations became evident, the instrument was moved about five miles (8 km) away to Goth Hill, a more radio-quiet location. But as Ottawa grew this site soon started becoming radio-noisy as well, due mostly to increasing air traffic at a nearby airport. Looking to improve the quality of their measurements, they proposed building a new solar telescope located far away from built up areas. Easy access from Ottawa
Ottawa
Ottawa is the capital of Canada, the second largest city in the Province of Ontario, and the fourth largest city in the country. The city is located on the south bank of the Ottawa River in the eastern portion of Southern Ontario...
made Algonquin a fairly obvious choice, although it was about 200 km away the roads were good quality and easy to travel.
Construction of the solar observation site started in 1959. The first instrument on the site was a new solar telescope, similar to Covington's original 4 ft (1.2 m) instrument, but slightly enlarged to 6 ft (1.8 m) which allowed it to better observe the entire solar disk. This instrument operated in parallel to the original at Goth Hill until 1962, when it took over these duties completely. A second 6 ft (1.8 m) telescope, identical to the one at ARO, was later installed at the Dominion Radio Astrophysical Observatory
Dominion Radio Astrophysical Observatory
The Dominion Radio Astrophysical Observatory is a research facility founded in 1960 and located south-west of Okanagan Falls, British Columbia, Canada. The site houses three instruments – an interferometric radio telescope, a 26-m single-dish antenna, and a solar flux monitor – and...
(DRAO) in Penticton, British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
as a backup.
Another solar instrument pattered on a different Goth Hill device followed, this one consisting of a series of thirty-two 10 ft (3 m) parabolic collectors connected to a common 700 ft (215 m) long waveguide
Waveguide
A waveguide is a structure which guides waves, such as electromagnetic waves or sound waves. There are different types of waveguides for each type of wave...
. Using phased array
Phased array
In wave theory, a phased array is an array of antennas in which the relative phases of the respective signals feeding the antennas are varied in such a way that the effective radiation pattern of the array is reinforced in a desired direction and suppressed in undesired directions.An antenna array...
techniques this instrument could image portions of the Sun's disk, compared to the single-dish instrument which saw the sun as a single unresolved "dot". The new instrument was up and running in 1966, adding to Covington's study of the sun by directly imaging the radio signal from sunspots and filaments.
Main instrument
Construction on the 150 ft (45.7 m) telescope started in the spring of 1964. The concrete base weighed 300 tons, the steel dish and the its rotating mount another 900 tons. An equatorial mountEquatorial mount
An equatorial mount is a mount for instruments that follows the rotation of the sky by having one rotational axis parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras...
in the base, only five feet high, positioned the instrument. The telescope was designed to operate at higher frequencies than existing instruments, requiring much of it to be constructed of flat plates instead of an open mesh in order to accurately focus these signals. The surface was built to be accurate to 1/5 of a centimeter, allowing it to accurately focus wavelengths to around 1.5 cm. Construction was completed in early 1966, and the telescope started operations in May 1966. Work was also completed a polar mounted paraboloid microwave horn and an 11 m equatorial mount dish north of the main antenna complex.
One of the earliest extended projects carried out on the instrument was the first successful very long baseline interferometry
Very Long Baseline Interferometry
Very Long Baseline Interferometry is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.Data...
(VLBI) experiment. Long Baseline Interferometry compares the signals from two or more telescopes, using the differences in phase between the signals to resolve the objects. Earlier experiments had used direct electrical links or microwave relays to extend the distance between the two telescopes, while still allowing real-time comparison of the phase of the two signals in a common instrument. However this limited the distance between the two instruments, to the distance the signal could travel while still remaining in-phase. The NRC invented a new technique that eliminated the need to directly compare the signals in real-time. Their technique used 2 inch Quadruplex videotape
2 inch Quadruplex videotape
2-inch quadruplex videotape was the first practical and commercially successful analog recording videotape format. It was developed and released for the broadcast television industry in 1956 by Ampex, an American company based in Redwood City, California...
to record the signals along with a clock signal from an atomic clock
Atomic clock
An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...
. The clock signal allowed the two signals to be later compared with the same accuracy that had formerly required direct realtime connections. NRC funded the installation of identical instruments at the ARO and a smaller telescope at DRAO. Combining the signals would simulated a single 3,074 km diameter radio telescope.
Having learned that the Americans were also attempting a similar VLBI experiment, they tried to be the first to successfully use the technique. Their target for the experiment was quasar
Quasar
A quasi-stellar radio source is a very energetic and distant active galactic nucleus. Quasars are extremely luminous and were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than...
3C 273. Recordings were made into the early morning of April 17, 1967. DRAOs tapes and atomic clock were shipped to the ARO for comparison, and after a month of trying to get the data to "line up", on May 21 they succeeded. After a few more days they had made the first highly accurate measurement of the size of the quasar, showing it was less than 100 light years across, about 1/1000 the span of the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
. Further experiments revealed the fact that 3C 273 had a distinct "jet".
In 1968 the 150 ft (45.7 m) telescope was used in a geodesy
Geodesy
Geodesy , also named geodetics, a branch of earth sciences, is the scientific discipline that deals with the measurement and representation of the Earth, including its gravitational field, in a three-dimensional time-varying space. Geodesists also study geodynamical phenomena such as crustal...
experiment that measured the distance between the ARO and space-tracking telescopes in Prince Albert, Saskatchewan
Prince Albert, Saskatchewan
Prince Albert is the third-largest city in Saskatchewan, Canada. It is situated in the centre of the province on the banks of the North Saskatchewan River. The city is known as the "Gateway to the North" because it is the last major centre along the route to the resources of northern Saskatchewan...
to 2143 km +/- 20 m. Other early experiments included a study of flare star
Flare star
A flare star is a variable star that can undergo unpredictable dramatic increases in brightness for a few minutes. It is believed that the flares on flare stars are analogous to solar flares in that they are due to magnetic reconnection in the atmospheres of the stars. The brightness increase is...
s by Queen's University
Queen's University
Queen's University, , is a public research university located in Kingston, Ontario, Canada. Founded on 16 October 1841, the university pre-dates the founding of Canada by 26 years. Queen's holds more more than of land throughout Ontario as well as Herstmonceux Castle in East Sussex, England...
. It was also used by Alan Bridle and Paul Feldman in 1974 for the first SETI
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...
search to be carried out at the 1.35 cm wavelength, emitted by water molecules in space.
Later uses
The original surface of the 150 ft (45.7 m) telescope consisted of a mix of aluminum mesh and plates. The mesh was almost transparent to wavelengths less than around a centimeter, and the plated area was not smooth enough to focus shorter wavelengths either. As attention in radio telescopy turned to shorter wavelengths, representing higher energy events, the ARO became less useful. After planning to resurface it so that it could operate at wavelengths as small as 3 mm, the NRC decided to close the ARO in 1987 and purchase a 25% share in the new James Clerk Maxwell TelescopeJames Clerk Maxwell Telescope
The James Clerk Maxwell Telescope is a submillimetre-wavelength telescope at Mauna Kea Observatory in Hawaii. Its primary mirror is 15 metres across: it is the largest astronomical telescope that operates in submillimetre wavelengths of the electromagnetic spectrum...
, which would include a radio telescope that could operate at 0.3 to 2 mm.
In 1988 the NRC invited the operators of the Hay River Radio Observatory in the Northwest Territories
Northwest Territories
The Northwest Territories is a federal territory of Canada.Located in northern Canada, the territory borders Canada's two other territories, Yukon to the west and Nunavut to the east, and three provinces: British Columbia to the southwest, and Alberta and Saskatchewan to the south...
, the Interstellar Electromagnetics Institute (IEI), to relocate their SETI
SETI
The search for extraterrestrial intelligence is the collective name for a number of activities people undertake to search for intelligent extraterrestrial life. Some of the most well known projects are run by the SETI Institute. SETI projects use scientific methods to search for intelligent life...
efforts to ARO. Due to budget cuts the NRC had been unable to use the ARO for research for some time, and were looking for low-cost projects that might be able to make use of the equipment. IEI jumped at the chance, and operated a SETI effort known as Project TARGET on the 18 m UofT telescope until 1991, when continuing budget cuts forced the NRC to cease operation of the site.
The continuing solar measurements, now used worldwide to predict communications problems due to sunspot
Sunspot
Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They are caused by intense magnetic activity, which inhibits convection by an effect comparable to the eddy current brake, forming areas of reduced surface temperature....
activity, were turned over to DRAO. At first the DRAO instrument was made "prime", and then once operation was demonstrated, the original Ottawa instrument was moved to join it as a hot backup
Failover
In computing, failover is automatic switching to a redundant or standby computer server, system, or network upon the failure or abnormal termination of the previously active application, server, system, or network...
.
The University of Toronto
University of Toronto
The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...
also operated their own 18 m telescope at the ARO for some time, after having moved it from the David Dunlap Observatory
David Dunlap Observatory
The David Dunlap Observatory is a large astronomical observatory site once owned by the University of Toronto, located just north of the city in Richmond Hill, Ontario within a estate. Its primary instrument is a 74-inch reflector telescope, at one time the second largest telescope in the world,...
which proved to be too close to the growing Toronto
Toronto
Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...
area. The smaller University of Toronto antenna and the 32-dish solar observatory were both donated to project TARGET, and have since been relocated to a new site near Shelburne, Ontario
Shelburne, Ontario
Shelburne, Ontario is a town in Dufferin County, Ontario, Canada, located at the intersection of Highway 10 and Highway 89...
.
The main ARO telescope was later operated by Natural Resources Canada
Natural Resources Canada
The Department of Natural Resources , operating under the FIP applied title Natural Resources Canada , is the ministry of the government of Canada responsible for natural resources, energy, minerals and metals, forests, earth sciences, mapping and remote sensing...
and the Space Geodynamics Laboratory, CRESTech, who used the telescope in VLBI projects to measure the movements of continental plates in geodetic surveys. They have made several upgrades to the main 150 ft (45.7 m) telescope after taking over operations, allowing it to track at higher speeds necessary to track satellite
Satellite
In the context of spaceflight, a satellite is an object which has been placed into orbit by human endeavour. Such objects are sometimes called artificial satellites to distinguish them from natural satellites such as the Moon....
s.
The telescope was used in ongoing VLBI experiments carried out by a worldwide consortium supported by the HALCA
HALCA
The HALCA , also known for its project name VSOP , or the code name MUSES-B for the second of the Mu Space Engineering Spacecraft series, is a Japanese 8 meter diameter radio telescope satellite which was used for Very Long Baseline Interferometry...
satellite, producing a 30,000 km-baseline telescope. The system is driven by the S2 software developed at York University
York University
York University is a public research university in Toronto, Ontario, Canada. It is Canada's third-largest university, Ontario's second-largest graduate school, and Canada's leading interdisciplinary university....
.
Current status
From 2008, the observatory has been operated by Thoth Technology who provide geodetic and deep space networkDeep Space Network
The Deep Space Network, or DSN, is a world-wide network of large antennas and communication facilities that supports interplanetary spacecraft missions. It also performs radio and radar astronomy observations for the exploration of the solar system and the universe, and supports selected...
services utilizing the 46 m antenna. The site is an active control point for the global positioning system
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
. The main antenna is equipped with receivers for the detection of L-band, S-band and X-band. The observatory's hydrogen maser
Hydrogen maser
A Hydrogen maser, also known as hydrogen frequency standard, is a specific type of maser that uses the intrinsic properties of the hydrogen atom to serve as a precision frequency reference....
maintains time standard stability to one part in 1015 in order to facilitate VLBI activities. By appointment ARO is open to visitors. Thoth also provides access to the site for activities such as York University
York University
York University is a public research university in Toronto, Ontario, Canada. It is Canada's third-largest university, Ontario's second-largest graduate school, and Canada's leading interdisciplinary university....
's space engineering field schools and research programs. For further information visit Algonquin Radio Observatory's official website.
Further reading
- To the Edge of the Universe, National Film Board of CanadaNational Film Board of CanadaThe National Film Board of Canada is Canada's twelve-time Academy Award-winning public film producer and distributor. An agency of the Government of Canada, the NFB produces and distributes documentary, animation, alternative drama and digital media productions...
, 1969 - a 22 minute documentary about the construction of the AGO and its use in the VLBI experiments.\
External links
- Official site
- Algonquin Radio Observatory - description from IEEE-Canada