The Hartebeesthoek Radio Astronomy Observatory (HartRAO) is a

radio astronomy Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation comin ...

observatory An observatory is a location used for observing terrestrial, marine, or celestial events. Astronomy, climatology/meteorology, geophysical, oceanography and volcanology are examples of disciplines for which observatories have been constructed. ...

, located in a natural bowl of hills at Hartebeesthoek just south of the

Magaliesberg The Magaliesberg (historically also known as ''Macalisberg'' or ''Cashan Mountains'') of northern South Africa, is a modest but well-defined mountain range composed mainly of quartzites. It rises at a point south of the Pilanesberg (and the Pi ...

mountain range,

Gauteng Gauteng ( ) is one of the nine provinces of South Africa. The name in Sotho-Tswana languages means 'place of gold'. Situated on the Highveld, Gauteng is the smallest province by land area in South Africa. Although Gauteng accounts for only ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

, about 50 km west of

Johannesburg Johannesburg ( , , ; Zulu language, Zulu and xh, eGoli ), colloquially known as Jozi, Joburg, or "The City of Gold", is the largest city in South Africa, classified as a Megacity#List of megacities, megacity, and is List of urban areas by p ...

. It is a National Research Facility run by South Africa's National Research Foundation. HartRAO was the only major radio astronomy observatory in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

until the construction of the

KAT-7 KAT-7 is a radio telescope situated in the Meerkat National Park, in the Northern Cape of South Africa. Part of the Karoo Array Telescope project, it is the precursor engineering test bed to the larger MeerKAT telescope, but it has become a scie ...

test bed for the future

MeerKAT MeerKAT, originally the Karoo Array Telescope, is a radio telescope consisting of 64 antennas in the Meerkat National Park, in the Northern Cape of South Africa. In 2003, South Africa submitted an expression of interest to host the Square Ki ...

array.

History

Entrance Hartebeesthoek Radio Astronomy Observatory (HartRAO)

The observatory was originally named Deep Space Station 51 (DSS51) and was built in 1961 by the

National Aeronautics and Space Administration The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding ...

(NASA). In this role the station assisted in tracking many unmanned

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

space missions, including the

Ranger A Ranger is typically someone in a military/paramilitary or law enforcement role specializing in patrolling a given territory, called “ranging”. The term most often refers to: * Park ranger or forest ranger, a person charged with protecting and ...

Surveyor Surveying or land surveying is the technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them. A land surveying professional is ...

and Lunar Orbiter spacecraft (which landed on the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

or mapped it from orbit), the Mariner missions (which explored the planets

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...

and

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

) and the Pioneer missions (which measured the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

's winds). The first

surface images from Mariner 4 were received at DSS 51. NASA withdrew from the station in 1975, handing it over to South Africa's

Council for Scientific and Industrial Research The Council for Scientific and Industrial Research (CSIR) is South Africa's central and premier scientific research and development organisation. It was established by an act of parliament in 1945 and is situated on its own campus in the c ...

(CSIR), who converted it to a radio astronomy observatory. In 1988 the observatory became a National Facility operated by the

Foundation for Research Development Foundation may refer to: * Foundation (nonprofit), a type of charitable organization ** Foundation (United States law), a type of charitable organization in the U.S. ** Private foundation, a charitable organization that, while serving a good caus ...

(FRD); in 1999 the FRD was restructured as the National Research Foundation (NRF). , NASA continues to contract for launch tracking services on an as-needed basis, and did so for the launch of the

Mars Science Laboratory Mars Science Laboratory (MSL) is a robotic space probe mission to Mars launched by NASA on November 26, 2011, which successfully landed ''Curiosity'', a Mars rover, in Gale Crater on August 6, 2012. The overall objectives include investigati ...

on 26 November 2011.

The Radio Telescope

The observatory is equipped with a single 260

ton Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of weight. Confusion can arise because ''ton'' can mean * the long ton, which is 2,240 pounds ...

radio telescope A radio telescope is a specialized antenna and radio receiver used to detect radio waves from astronomical radio sources in the sky. Radio telescopes are the main observing instrument used in radio astronomy, which studies the radio frequency ...

with a main reflecting surface

diameter In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints lie on the circle. It can also be defined as the longest chord of the circle. Both definitions are also valid f ...

of 26 metres. The telescope is equipped with

radio Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a tr ...

receivers operating in the

microwave Microwave is a form of electromagnetic radiation with wavelengths ranging from about one meter to one millimeter corresponding to frequencies between 300 MHz and 300 GHz respectively. Different sources define different frequency ra ...

band at wavelengths of 18 cm, 13 cm, 6 cm, 4.5 cm, 3.5 cm, 2.5 cm and 1.3 cm.

Research

HartRAO is used for continuum

radiometry Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which ch ...

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter ...

pulsar A pulsar (from ''pulsating radio source'') is a highly magnetized rotating neutron star that emits beams of electromagnetic radiation out of its magnetic poles. This radiation can be observed only when a beam of emission is pointing toward Ea ...

timing and

interferometry Interferometry is a technique which uses the '' interference'' of superimposed waves to extract information. Interferometry typically uses electromagnetic waves and is an important investigative technique in the fields of astronomy, fiber o ...

. It works together with radio telescopes in other continents as well as the orbiting radio telescopes HALCA (VSOP project) and Spektr-R (RadioAstron) in order to perform Very Long Baseline 😁Interferometry (VLBI) observations. HartRAO is an associate member of the

European VLBI Network The European VLBI Network (EVN) is a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa and Puerto Rico, which performs very high angular resolution observations of cosmic radio sources usin ...

, but also operates with the Australia Telescope Long Baseline Array, the Asia-Pacific Telescope, the United States Very Long Baseline Array and the Global Array. HartRAO also runs a Space Geodesy programme using VLBI,

Satellite laser ranging In satellite laser ranging (SLR) a global network of observation stations measures the round trip time of flight of ultrashort pulses of light to satellites equipped with retroreflectors. This provides instantaneous range measurements of milli ...

and the

Global Positioning System The Global Positioning System (GPS), originally Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of the global navigation satellite ...

. Development work of a Lunar Laser Ranger (LLR) has commenced, based on a 1 m optical telescope. The LLR system will use a 100 mJ, 20 Hz, 80 ps pulse length laser to range to corner cube reflector arrays on the Moon. The observatory also provides students and lecturers from South African universities the facilities and opportunities to perform research.

Involvement with the Karoo Array Telescope Project

The XDM, a prototype dish for the

radio telescope, was constructed at HartRAO. The XDM dish design was first used in

, a seven-dish engineering testbed and science instrument in Carnarvon in the

Northern Cape Province The Northern Cape is the largest and most sparsely populated province of South Africa. It was created in 1994 when the Cape Province was split up. Its capital is Kimberley. It includes the Kalahari Gemsbok National Park, part of the Kgalagadi ...

. KAT-7, completed in 2012, marked the first stage of MeerKAT development.

References

External links