John Evan Baldwin FRS (6 December 1931 – 7 December 2010) was a British

astronomer An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...

who worked at the

Cavendish Astrophysics Group The Cavendish Astrophysics Group (formerly the Radio Astronomy Group) is based at the Cavendish Laboratory at the University of Cambridge. The group operates all of the telescopes at the Mullard Radio Astronomy Observatory except for the 32m MERLI ...

Astrophysics Group members - John Baldwin
''mrao.cam.ac.uk'' (formerly Mullard Radio Astronomy Observatory) from 1954. He played a role in the development of

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 opt ...

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 coming f ...

, and later astronomical

optical 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 opt ...

and

lucky imaging Lucky imaging (also called lucky exposures) is one form of speckle imaging used for astrophotography. Speckle imaging techniques use a high-speed camera with exposure times short enough (100 ms or less) so that the changes in the Earth's atm ...

. He made the first maps of the radio emission from the

Andromeda Galaxy The Andromeda Galaxy (IPA: ), also known as Messier 31, M31, or NGC 224 and originally the Andromeda Nebula, is a barred spiral galaxy with the diameter of about approximately from Earth and the nearest large galaxy to the Milky Way. The gala ...

and the

Perseus Cluster The Perseus cluster (Abell 426) is a Galaxy cluster, cluster of galaxies in the constellation Perseus (constellation), Perseus. It has a recession speed of 5,366 km/second, s and a diameter of 863′. It is one of the most massive object ...

, and measured the properties of many

active galaxies An active galactic nucleus (AGN) is a compact region at the center of a galaxy that has a much-higher-than-normal luminosity over at least some portion of the electromagnetic spectrum with characteristics indicating that the luminosity is not pr ...

. In 1985 he performed the first Aperture Masking Interferometry observations, and then led the construction and operation of the

Cambridge Optical Aperture Synthesis Telescope COAST, the Cambridge Optical Aperture Synthesis Telescope, is a multi-element optical astronomical interferometer with baselines of up to 100 metres, which uses aperture synthesis to observe stars with angular resolution as high as one thousandt ...

, and helped develop the

method. In 2001 he was awarded the

Jackson-Gwilt Medal The Jackson-Gwilt Medal is an award that has been issued by the Royal Astronomical Society (RAS) since 1897. The original criteria were for the invention, improvement, or development of astronomical instrumentation or techniques; for achievement ...

for his technical contributions to the fields of

and

aperture synthesis Aperture synthesis or synthesis imaging is a type of interferometry that mixes signals from a collection of telescopes to produce images having the same angular resolution as an instrument the size of the entire collection. At each separation an ...

. He matriculated as a member of

Queens' College, Cambridge Queens' College is a constituent college of the University of Cambridge. Queens' is one of the oldest colleges of the university, founded in 1448 by Margaret of Anjou. The college spans the River Cam, colloquially referred to as the "light s ...

in 1949 and was a Life Fellow of the College from 1999 to his death in 2010.

References

External links

- John Baldwin's page at the MRAO

- Photo of John Baldwin
with

Jan Hendrik Oort Jan Hendrik Oort ( or ; 28 April 1900 – 5 November 1992) was a Dutch astronomer who made significant contributions to the understanding of the Milky Way and who was a pioneer in the field of radio astronomy. His ''New York Times'' obituary ...

, Bob Rubin and Vera Rubin 1931 births 2010 deaths 20th-century British astronomers Alumni of Queens' College, Cambridge Fellows of Queens' College, Cambridge Fellows of the Royal Society {{UK-astronomer-stub