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Radio Astronomy Summer School – 2008
Introduction – Early History of Radio Astronomy
Tatsuhiko Hasegawa (ASIAA)
1. Radio astronomy was interferometry from the beginning.
2. Closely related to developments in engineering and society.
3. We need to reduce radio noise and to protect radio
frequencies.
1870 Maxwell – Theory of Electromagnetic Wave.
1889 Hertz – Laboratory Generation and Detection of Radio Electromagnetic Wave.
Many scientists attempted to detect Solar radio emission in m-cm bands – all failed.
1901 Planck – Theory of Thermal Blackbody Radiation => Solar thermal radiation will be weak in m-cm band.
Marconi – First long-distance radio communication (across Atlantic ocean).
1902 Heaviside and Kennelly – Earth ionosphere reflects radio waves. Turned out only freq < 20 M Hz.
1920-30 Commercial radio telephone service.
1933 Jansky discovers cosmic radio wave from Galactic center at 20.5 M Hz.
1940 Reber builds a radio telescope and maps cosmic radio emission (from Galactic plane) at 162 M Hz.
1941 – 45 Hey, Southworth, Reber (separately) observed Solar radio emission. Radar technology advanced.
1945 – 1950 Pawsey (Australia), Ryle (UK) developed interferometry technique. Ryle & Vonberg (Cambridge
UK) built a 2-element interferometer and detected Solar flares and Cas A. Bolton & Stanley (Au) used 'Sea
interferometry'. 10 compact radio sources were discovered by 1948. Ryle, Smith, Elsmore made first catalog
of point radio sources (1C catalog, 1949). Antenna movements and use of Earth rotation. Many dipole
antennas to form an interferometer (Mills Au). Many small dishes in cross-pattern (Christiansen Au)
1951 First detection of the 21cm line of H I. Ewen & Percell (US). Muller & Oort (D). Pawsey (Au).
1955 26m (Dutch). 1956 18m (Harvard). 1957 76m (UK).
1958 27m x 2 (Caltech). 26m (US Navy). 1959 26m (Michigan). 26m (NRAO). 22m (USSR)
1960 – 63 Discoveries of radio galaxies.
1961 Parks 64m (Au). 25m x 2 (Melbourne, Au). 1962 90m (NRAO). 1963 300m (Arecibo, US).
1963 18m x 3 (Ryle 1-mile UK). 1964 36m (Mark II, UK). 36m (Haystack, US). 1965 42m (GB). 46m (Ca).
1965 3K cosmic microwave background radiation. 1967 Discovery of pulsars.
1975 Nobel prize : Martin Ryle & Antony Hewish for contributions to radio astronomy.
1978 Nobel prize : Penzias & Wilson for the discovery of cosmic background radiation.
Karl Jansky and his rotating antenna in New Jersey (1928). Courtesy of NRAO/AUI. Jansky, working at
Bell Telephone Laboratory, investigated the origin of static noise for radio telephone service.
Grote Reber's telescope in his
backyard in Illinois (1938).
Reber was a radio engineer.
Courtesy of NRAO.
Arno Penzias and Robert Woodrow Wilson (1965) at Bell Laboratory built
this radiometer intended for satellite communication and radio astronomy
experiments. They encountered an excess antenna temperature of 3.5 K.
They could not explain the excess. This led to the discovery of the cosmic
microwave background radiation. Courtesy NASA.
(http://grin.hq.nasa.gv/ABSTRACTS/GPN-2003-00013.html)
NRAO 25.5m #1 (1958) at Green Bank
Green Bank 90m telescope (1962) before and after
the collapse on Nov 15, 1988.
Early Activities in Radio Astronomy in the United
Kingdom – Courtesy Jodrell Bank Observatory
and University of Manchester
Parabolic reflecting wires (65 m long) at
Jodrell Bank (1947)
Jodrell Bank Mark I 75m (1957)
First day at Jodrell Bank (1945 Dec)
Jocelyn Burnell and the 4.5 acre (135 m x 135 m ) array (U of Cambridge)
that was used in the discovery of pulsars (1967). Courtesy University of
Manchester. ( www.jb.man.ac.uk/distance/life/seti/ ) The facility was
intended for Solar radio monitoring. The supervisor was Dr. Hewish.
Eight Yagi-antennas (1951)
A reflector using a hole in the ground (1953)
Early activities in radio
astronomy in Australia
at WW II radar station.
Courtesy ATNF and
CSIRO.
Two Yagi-antennas (1947)
Cygnus-A detection chart by 'sea interferometry' (1948).
Modern Radio Telescopes in Australia
Courtesy ATNF / CSIRO
Compact Array at Narrabi (1988)
Parkes 64m and 18m (1963)
Early Activities in Radio
Astronomy in The Netherlands
Courtesy ASTRON Westerbork
Observatory
HI 21cm line was detected and mapped with this 7.5 m telescope
(originally a German military radar dish) in Kootwijk, Holland (19511956). Prof. Jan Oort was eager to exploit the radio technique.
Dwingeloo 25m (1956)
Wsterbork 25m x 12 (E-W) (in 1970)