Radio astronomy

radio astronomerradioradioastronomyradio astronomersradio astronomicalAstronomyradio astrophysicsradio sourceradioastronomicalradio emissions
Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies.wikipedia
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Karl Guthe Jansky

Karl JanskyKarl G. JanskyJansky
The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way.
He is considered one of the founding figures of radio astronomy.

Radio telescope

radio telescopesradiotelescoperadio-telescope
Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis.
A radio telescope is a specialized antenna and radio receiver used to receive radio waves from astronomical radio sources in the sky in radio astronomy.

Quasar

quasarsquasi-stellar objectQSO
These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers.
But when radio astronomy commenced in the 1950s, astronomers detected, among the galaxies, a small number of anomalous objects with properties that defied explanation.

Astronomical interferometer

astronomical interferometryinterferometerinterferometry
Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis.
Interferometry is most widely used in radio astronomy, in which signals from separate radio telescopes are combined.

Bell Labs

Bell Telephone LaboratoriesBell LaboratoriesAT&T Bell Laboratories
The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way. Later that year George Clark Southworth, at Bell Labs like Jansky, also detected radiowaves from the sun.
Researchers working at Bell Labs are credited with the development of radio astronomy, the transistor, the laser, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages C, C++, and S.

Aperture synthesis

aperture synthesis imagingsynthetic apertureinterferometric imaging
Radio astronomy is conducted using large radio antennas referred to as radio telescopes, that are either used singularly, or with multiple linked telescopes utilizing the techniques of radio interferometry and aperture synthesis. Martin Ryle and Antony Hewish at the Cavendish Astrophysics Group developed the technique of Earth-rotation aperture synthesis.
Astronomical interferometers are commonly used for high-resolution optical, infrared, submillimetre and radio astronomy observations.

Milky Way

galaxyMilky Way Galaxyour galaxy
The first detection of radio waves from an astronomical object was in 1932, when Karl Jansky at Bell Telephone Laboratories observed radiation coming from the Milky Way.
The Galactic Center is marked by an intense radio source named Sagittarius A* (pronounced Sagittarius A-star).

Grote Reber

Reber, Grote
Grote Reber was inspired by Jansky's work, and built a parabolic radio telescope 9m in diameter in his backyard in 1937.
Grote Reber (December 22, 1911 – December 20, 2002) was a pioneer of radio astronomy, which combined his interests in amateur radio and amateur astronomy.

Elizabeth Alexander (scientist)

Elizabeth AlexanderElizabeth Alexander,Elizabeth Caldwell
Several other people independently discovered solar radiowaves, including E. Schott in Denmark and Elizabeth Alexander working on Norfolk Island.
Frances Elizabeth Somerville Alexander (née Caldwell; 13 December 1908 – 15 October 1958) was a British geologist, academic, and physicist, whose wartime work with radar and radio led to early developments in radio astronomy and whose post-war work on the geology of Singapore is considered a significant foundation to contemporary research.

Jansky

JymJymilliJansky
His pioneering efforts in the field of radio astronomy have been recognized by the naming of the fundamental unit of flux density, the jansky (Jy), after him.
The jansky (symbol Jy, plural janskys) is a non-SI unit of spectral flux density, or spectral irradiance, used especially in radio astronomy.

Antony Hewish

Tony HewishHewishHewish, Anthony
Martin Ryle and Antony Hewish at the Cavendish Astrophysics Group developed the technique of Earth-rotation aperture synthesis.
Antony Hewish (born 11 May 1924) is a British radio astronomer who won the Nobel Prize for Physics in 1974 (together with fellow radio-astronomer Martin Ryle) for his role in the discovery of pulsars.

Martin Ryle

Sir Martin RyleRyleM. Ryle
Martin Ryle and Antony Hewish at the Cavendish Astrophysics Group developed the technique of Earth-rotation aperture synthesis. The difficulty in achieving high resolutions with single radio telescopes led to radio interferometry, developed by British radio astronomer Martin Ryle and Australian engineer, radiophysicist, and radio astronomer Joseph Lade Pawsey and Ruby Payne-Scott in 1946.
Sir Martin Ryle (27 September 1918 – 14 October 1984) was an English radio astronomer who developed revolutionary radio telescope systems (see e.g. aperture synthesis) and used them for accurate location and imaging of weak radio sources.

Electromagnetic interference

interferenceradio frequency interferenceradio interference
Finally, transmitting devices on earth may cause radio-frequency interference.
It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy.

Ruby Payne-Scott

The difficulty in achieving high resolutions with single radio telescopes led to radio interferometry, developed by British radio astronomer Martin Ryle and Australian engineer, radiophysicist, and radio astronomer Joseph Lade Pawsey and Ruby Payne-Scott in 1946.
Ruby Violet Payne-Scott, BSc (Phys) MSc DipEd (Syd) (28 May 1912 – 25 May 1981) was an Australian pioneer in radiophysics and radio astronomy, and was the first female radio astronomer.

Galaxy

galaxiesgalacticgalactic nuclei
These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers.
The first non-visual study of galaxies, particularly active galaxies, was made using radio frequencies.

Sidereal time

sidereal daysidereallocal sidereal time
Jansky discussed the puzzling phenomena with his friend, astrophysicist and teacher Albert Melvin Skellett, who pointed out that the time between the signal peaks was the exact length of a sidereal day; the time it took for "fixed" astronomical objects, such as a star, to pass in front of the antenna every time the Earth rotated.
Beginning in the 1970s the radio astronomy methods Very Long Baseline Interferometry (VLBI) and pulsar timing overtook optical instruments for the most precise astrometry.

Astrophysical maser

masermasersmaser emission
These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers.
Astronomical masers remain an active field of research in radio astronomy and laboratory astrophysics due, in part, to the fact that they are valuable diagnostic tools for astrophysical environments which may otherwise elude rigorous quantitative study and because they may facilitate the study of conditions which are inaccessible in terrestrial laboratories.

Radar

radar stationradarsradar system
At Cambridge University, where ionospheric research had taken place during World War II, J.A. Ratcliffe along with other members of the Telecommunications Research Establishment that had carried out wartime research into radar, created a radiophysics group at the university where radio wave emissions from the Sun were observed and studied.
Passive radar is applicable to electronic countermeasures and radio astronomy as follows:

Very Large Array

VLAEVLAD. S. Heeschen
For example, the Very Large Array has 27 telescopes giving 351 independent baselines at once.
The Karl G. Jansky Very Large Array (VLA) is a centimeter-wavelength radio astronomy observatory located in central New Mexico on the Plains of San Agustin, between the towns of Magdalena and Datil, ~50 miles (80 km) west of Socorro.

Very-long-baseline interferometry

very long baseline interferometryVLBIlong-baseline interferometry
Beginning in the 1970s, improvements in the stability of radio telescope receivers permitted telescopes from all over the world (and even in Earth orbit) to be combined to perform very-long-baseline interferometry.
Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy.

Joseph Lade Pawsey

Joseph L. PawseyDr Joseph Lade PawseyJ L Pawsey
The difficulty in achieving high resolutions with single radio telescopes led to radio interferometry, developed by British radio astronomer Martin Ryle and Australian engineer, radiophysicist, and radio astronomer Joseph Lade Pawsey and Ruby Payne-Scott in 1946.
At the end of World War II he became a pioneer of the new science of radio astronomy, his interest being stirred by the discovery of radio waves from the Galaxy and by reports of intense interference in metre-wave radar receivers caused by disturbances on the Sun.

Channel 37

37UHF Channel 37
Channel 37
The frequency range allocated to this channel is important for radio astronomy, so broadcasting is not licensed.

Radar astronomy

radarRadar observationsplanetary radar
Radar astronomy
Radar astronomy differs from radio astronomy in that the latter is a passive observation and the former an active one.

George Clark Southworth

G.C. SouthworthGeorge C. SouthworthSouthworth
Later that year George Clark Southworth, at Bell Labs like Jansky, also detected radiowaves from the sun.
Southworth received the Morris N. Liebmann Award in 1938, and the IEEE Medal of Honor in 1963 "For pioneering contributions to microwave radio physics, to radio astronomy, and to waveguide transmission."

Infrared astronomy

infraredinfrared radiationJ, H, and K s bands
Infrared astronomy
After a number of discoveries were made in the 1950s and 1960s in radio astronomy, astronomers realized the information available outside the visible wavelength range, and modern infrared astronomy was established.