Roger Clifton Jennison
   HOME

TheInfoList



OR:

Roger Clifton Jennison (18 December 1922 – 29 December 2006) worked as a radio astronomer at
Jodrell Bank Jodrell Bank Observatory ( ) in Cheshire, England hosts a number of radio telescopes as part of the Jodrell Bank Centre for Astrophysics at the University of Manchester. The observatory was established in 1945 by Bernard Lovell, a radio astron ...
under the guidance of
Robert Hanbury Brown Robert Hanbury Brown, AC FRS (31 August 1916 – 16 January 2002) was a British astronomer and physicist born in Aruvankadu, India. He made notable contributions to the development of radar and later conducted pioneering work in the field of ...
. Jennison made a number of discoveries in the field of
radio astronomy Radio astronomy is a subfield of astronomy that studies Astronomical object, celestial objects using radio waves. It started in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observat ...
, including the discovery of the double nature of radio source
Cygnus A Cygnus A ( 3C 405) is a radio galaxy, one of the strongest radio sources in the sky. Discovery and Identification A concentrated radio source in Cygnus was discovered by Grote Reber in 1939. In 1946 Stanley Hey and his colleague James Phillip ...
( 3C 405.0) with M K Das Gupta and the mapping of
Cassiopeia A Cassiopeia A (Cas A) () is a supernova remnant (SNR) in the constellation Cassiopeia and the brightest extrasolar radio source in the sky at frequencies above 1 GHz. The supernova occurred approximately away within the Milky Way; ...
with V Latham.


Early life

Jennison was born in
Grimsby Grimsby or Great Grimsby is a port town in Lincolnshire, England with a population of 86,138 (as of 2021). It is located near the mouth on the south bank of the Humber that flows to the North Sea. Grimsby adjoins the town of Cleethorpes dir ...
,
England England is a Countries of the United Kingdom, country that is part of the United Kingdom. It is located on the island of Great Britain, of which it covers about 62%, and List of islands of England, more than 100 smaller adjacent islands. It ...
, in 1922. His education was at Clee Grammar School for Boys. He was commissioned from RAF aircrew to the Technical Branch-Signals, where he developed
radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...
and
microwave Microwave is a form of electromagnetic radiation with wavelengths shorter than other radio waves but longer than infrared waves. Its wavelength ranges from about one meter to one millimeter, corresponding to frequency, frequencies between 300&n ...
systems using the
magnetron The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave oven, microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of ...
.


Radio astronomy

In the 1950s he developed a new observable for obtaining information about visibility phases in an
interferometer 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 opt ...
when delay errors are present called the closure phase. He performed the first measurements of closure phase at optical wavelengths. Jennison saw greater potential for his technique in radio interferometry, and proposed that it should be tested on a three-element radio interferometer at
Jodrell Bank Jodrell Bank Observatory ( ) in Cheshire, England hosts a number of radio telescopes as part of the Jodrell Bank Centre for Astrophysics at the University of Manchester. The observatory was established in 1945 by Bernard Lovell, a radio astron ...
. In 1958 he successfully demonstrated its effectiveness at radio wavelengths, but it only became widely used for long baseline radio interferometry in 1974. A minimum of three antennas are required. This method was used for the first
VLBI Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth or in space. T ...
measurements, and a modified form of this approach ("Self-Calibration") is still used today at
radio Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3  hertz (Hz) and 300  gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...
,
optical Optics is the branch of physics that studies the behaviour and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behaviour of visible, ultravio ...
and
infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
wavelengths.


Academic career

Jennison was appointed to the
University of Kent The University of Kent (formerly the University of Kent at Canterbury, abbreviated as UKC) is a Collegiate university, collegiate public university, public research university based in Kent, United Kingdom. The university was granted its roya ...
at
Canterbury Canterbury (, ) is a City status in the United Kingdom, city and UNESCO World Heritage Site, in the county of Kent, England; it was a county borough until 1974. It lies on the River Stour, Kent, River Stour. The city has a mild oceanic climat ...
in 1965 and was the first Professor of Physical Electronics at the University. Within a year he established the Electronics Laboratory (later Department of Electronics and now School of Engineering and Digital Arts) at the University. Prior to his appointment at Kent he was Senior Lecturer in Radio Astronomy at Jodrell Bank Observatory and Senior Lecturer in Physics,
Manchester University The University of Manchester is a public university, public research university in Manchester, England. The main campus is south of Manchester city centre, Manchester City Centre on Wilmslow Road, Oxford Road. The University of Manchester is c ...
. His research interests extended to relativity, studying paths of light in rotating systems, and also to studying water divining and
ball lightning Ball lightning is a rare and unexplained phenomenon described as Luminosity, luminescent, spherical objects that vary from pea-sized to several meters in diameter. Though usually associated with thunderstorms, the observed phenomenon is repor ...
. With the latter, Jennison reported his personal encounter with the phenomenon as an airline passenger during a flight in March 1963, when a glowing ball of light was created inside the aircraft following a lightning strike. After retirement he was appointed as the emeritus professor of physical electronics at the University of Kent. He died on 29 December 2006. The building which he helped design to house the Electronics Laboratory, now the seat of the School of Engineering and Digital Arts, was named after him by the University of Kent in 2009.


Interest in the arts

Jennison was a co-founder of the Canterbury Society of Art and was involved in the activities of the Canterbury Arts Council. He was also a fellow of the
Royal Astronomical Society The Royal Astronomical Society (RAS) is a learned society and charitable organisation, charity that encourages and promotes the study of astronomy, planetary science, solar-system science, geophysics and closely related branches of science. Its ...
, the
Institution of Electrical Engineers The Institution of Electrical Engineers (IEE) was a British professional organisation of electronics, electrical, manufacturing, and information technology professionals, especially electrical engineers. It began in 1871 as the Society of Tel ...
and the
Royal Society of Arts The Royal Society for the Encouragement of Arts, Manufactures and Commerce, commonly known as the Royal Society of Arts (RSA), is a learned society that champions innovation and progress across a multitude of sectors by fostering creativity, s ...
. Roger Clifton Jennison's interest in the arts may have been stimulated by his father, George Robert Jennison, who was a well-known portrait painter in his home town of Grimsby and whose work is still on display in
Grimsby Town Hall Grimsby Town Hall is a municipal building in Town Hall Square in Grimsby, Lincolnshire, England. The building, which is the meeting place of North East Lincolnshire Council, is a Grade II listed building. History The first town hall in Grimsby ...
.


References


External links


School of Engineering and Digital Arts (formerly Department of Electronics), University of Kent

A phase sensitive interferometer technique for the measurement of the Fourier transforms of spatial brightness distributions of small angular extent

Canterbury Society of Art
{{DEFAULTSORT:Jennison, Roger 20th-century British astronomers 1922 births 2006 deaths Radio astronomers