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Radio Telescope
Grote Reber was born in Chicago on December 22, 1911. He received a BS
in 1933 from the Illinois Institute of Technology in Chicago, where he
studied radio engineering. While still a student, he became very
interested in radio astronomy - in 1932 he learned about Karl Jansky's
discovery of cosmic radio waves and wanted to learn more. He wondered
whether the waves were coming only from the galaxy or from other
celestial objects, and how the radio waves were produced. <more>
During the 1930s Reber attempted to get a job working with Jansky,
who was at Bell Labs at the time, to study cosmic radio waves. But since
the economy was in a slump as the Great Depression swept over the
country, the Labs werent hiring. So, Reber decided to study radio
astronomy on his own. Meanwhile, he worked for various radio
manufacturers in Chicago from 1933 to 1947.
In 1937, Reber came up with a design for a radio telescope, which he
constructed in his back yard in Wheaton, Illinois, a suburb of Chicago.
He built the telescope in his free time at his own expense. The
telescopes mirror was made of sheet metal 31.4 feet in diameter, and
was able to focus radio waves to a point 20 feet above the dish. The
telescope also featured a cylinder containing a radio receiver which
amplified the faint cosmic signals by a factor of several million. This
made them strong enough to be recorded and charted. Reber knew that it
would be important to observe a wide range of wavelengths of radiation
from the sky in order to understand how the radiation was being
produced. He achieved this by including a parabolic dish reflector in
the scope, which has a shape that is usable over a wide wavelength
range.
Thus, Reber spent long hours every night scanning the skies with his
telescope. In 1938, he was successful in detecting radio emission from
the Milky Way, confirming Jansky's earlier discovery. He later presented
his data ¹ which was essentially a survey of radio radiation from the
sky. He did so using contour maps showing the brightest areas as the
richest radio sources. He published the first surveys of radio waves
from the sky in engineering and astronomy journals in the late 1930s and
early 1940s, establishing a major field of research. Later, research
groups in many countries began building bigger and better antennas and
receivers to follow up on his discoveries.
Reber donated his original radio telescope to the National Radio
Astronomy Observatory at Green Bank, West Virginia, and supervised its
assembly there in the early 1960s. It remains there as a historical
monument. In the 1950s, Reber sought a field that seemed neglected by
most other researchers and turned his attention to cosmic radio waves at
very low frequencies (1-2 MHz, or wavelength 150-300 meters). Waves of
these frequencies cannot penetrate the Earth's ionosphere except in
certain parts of the planet at times of low solar activity. One such
place is Tasmania, where Reber resides to this day (Jan. 2002).
Reber worked as a Radio Physicist at the National Bureau of Standards
from 1947 to 1951. From 1951 on, he has been conducting radio astronomy
investigations in Hawaii and Tasmania. He is also currently Honorary
Research Fellow of the Division of Radio Physics of the Australian
Commonwealth Scientific and Industrial Research Organization. He is a
member of the American Astronomical Society, and has received a number
of awards for his work. In 1962, he was the recipient of the Bruce gold
medal of the Astronomical Society of the Pacific. In 1963, he received
an Elliot Cresson gold medal from the Franklin Institute of
Pennsylvania, Philadelphia. In 1976 he received the Jansky prize of the
National Radio Astronomy Observatory.
[January 2002]
[Orignal article can be found at
http://web.mit.edu/invent/iow/reber.html] |
