Ernest Leonard Johnson (1891–1977) was a South African astronomer and a former staff member of the

Union Observatory Union Observatory also known as Johannesburg Observatory ( 078) is a defunct astronomical observatory in Johannesburg, South Africa that was operated between 1903 and 1971. It is located on Observatory Ridge, the city's highest point at 1,808 met ...

in Johannesburg, South Africa. He is known for the discovery of 18

asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...

s between 1946–1951, as well as several comets. On 25 August 1949, he discovered 48P/Johnson, a periodic comet expected to pass no closer than 1.2 to 1.3 AU from our planet in 2025. Johnson received the "Donohoe Comet Medal" twice before retiring in 1956. He died in 1977.

Biography

Johnson was the son of William Johnson, a medical practitioner, and Rachel Sarah Joan Sanderson. He matriculated at

Grey College, Bloemfontein Grey College (Afrikaans: ''Grey Kollege'') is a semi-private English & Afrikaans medium school for boys situated in the suburb of Universitas in Bloemfontein in the Free State province of South Africa, it is one of the 23 Milner Schools. Th ...

, South Africa and started working on a mine but when his brother, Cecil Robert Johnson, was killed in a mining accident he applied for a position at the

in Johannesburg, South Africa. He started work there as a learner astronomer in 1914. He served in the armed forces of the Union of South Africa in World War I (1914-1918) during the campaign in German West Africa (now Namibia) but was sent home owing to illness. He recovered and went to England where he served as a bomber pilot for the

Royal Flying Corps "Through Adversity to the Stars" , colors = , colours_label = , march = , mascot = , anniversaries = , decorations ...

. After the war he returned to the Union Observatory and remained there for the rest of his career. Johnson produced star maps of the sky south of 19 degrees south

declination In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...

, in collaboration with

Harry Edwin Wood Harry Edwin Wood (3 February 1881 – 27 February 1946) was an English astronomer, director of the Union Observatory in Johannesburg, and discoverer of minor planets. Wood was born in Manchester, graduating from Manchester University in 1902 w ...

. In January 1935 he discovered a faint comet, that was visible for less than two months, while searching the sky in declination 52 degrees south. This comet was named ''Johnson's comet 1935''. He discovered a second comet in 1948. Between August 1946 and July 1951, Johnson also discovered 18

s, the most important of which was named

1580 Betulia 1580 Betulia, provisional designation , is an eccentric, carbonaceous asteroid, classified as near-Earth object of the Amor group, approximately 4.2 kilometers in diameter. It was discovered on 22 May 1950, by South African astronomer Ernest Jo ...

. This asteroid was discovered on 22 May 1950 during its close approach to the earth. From 1921 to 1953, his observations of the asteroids and more than 30 comets were published in the ''Circular of the Union Observatory, Johannesburg''. Johnson was a member of the

Astronomical Society of Southern Africa The Astronomical Society of Southern Africa (ASSA), formed in 1922, is a widespread body consisting of both amateur and professional astronomers. There are eight autonomous centres throughout Southern Africa. History The Cape Astronomical Associ ...

and contributed to the society's ''Monthly Notes''.

List of discoveries

Comets

Discoveries of comets include: * C/1935 A1 on 8 January 1935 (Comet ''a'' 1935) * C/1948 R1 on 1 September 1948 (Comet 1948 ''j'') * 48P/Johnson on 25 August 1949 * C/1949 K1 on 20 May 1949 (Comet 1949 ''a'' and/or 1949 ''d'')

Asteroids

Johnson is credited by the

Minor Planet Center The Minor Planet Center (MPC) is the official body for observing and reporting on minor planets under the auspices of the International Astronomical Union (IAU). Founded in 1947, it operates at the Smithsonian Astrophysical Observatory. Function ...

with the discovery of 18 asteroids:.

Private life

In 1922 Johnson married Aisleen Devenish, with whom he had a daughter and a son. He retired from the observatory in December 1951 but continued to work until 1956, during which time he tested potential astronomical sites with portable reflecting telescopes for the

European Southern Observatory The European Organisation for Astronomical Research in the Southern Hemisphere, commonly referred to as the European Southern Observatory (ESO), is an intergovernmental organization, intergovernmental research organisation made up of 16 mem ...

Organisation.

References

*Vermeulen, D.J. (2006) ''Living amongst the stars at the Johannesburg Observatory.'' Johannesburg: Chris van Rensburg Publications

External links

Biographical Index to MNASSA and JASSA
Prepared by I S Glass in 2003 (archived on 4 February 2012)
A history of comet discovery from South Africa
T P Cooper, August 2003 {{DEFAULTSORT:Johnson, Ernest Leonard 1891 births 1977 deaths Discoverers of asteroids * South African astronomers South African scientists