Ernest Leonard Johnson

Ernest Leonard Johnson (1891–1977) was a South African astronomer and a former staff member of the Union Observatory in Johannesburg, South Africa. He is known for the discovery of 18 asteroids between 1946–1951, as well as several comets.[1] 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.[2] Johnson received the "Donohoe Comet Medal" twice[3]: 40  before retiring in 1956. He died in 1977.[4]

Ernest Leonard Johnson
Born(1891-12-21)21 December 1891
Bloemfontein, Orange Free State
Died1977 (aged 85–86)
South Africa
NationalitySouth African
EducationGrey College
Known forDiscovery of 4 comets and 18 Asteroids
SpouseAisleen Devenish (married 1922)
AwardsDonohoe Comet Medal
Scientific career
FieldsAstronomy
InstitutionsUnion Observatory, Johannesburg
Minor planets discovered: 18 [1]
see § List of discovered minor planets

Biography

Johnson was the son of William Johnson, a medical practitioner, and Rachel Sarah Joan Sanderson.[4] He matriculated at Grey College, Bloemfontein, 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 Union Observatory in Johannesburg, South Africa. He started work there as a learner astronomer in 1914.[5]

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. After the war he returned to the Union Observatory and remained there for the rest of his career.[5]

Johnson produced star maps of the sky south of 19 degrees south declination, in collaboration with Harry Edwin Wood. 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.[5]

Between August 1946 and July 1951, Johnson also discovered 18 asteroids, the most important of which was named 1580 Betulia. 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.[5]

Johnson was a member of the Astronomical Society of Southern Africa and contributed to the society's Monthly Notes.[5]

List of discoveries

Comets

Discoveries of comets include:

  • C/1935 A1 on 8 January 1935 (Comet a 1935)[6]
  • C/1948 R1 on 1 September 1948 (Comet 1948 j)[7]
  • 48P/Johnson on 25 August 1949[2]
  • C/1949 K1 on 20 May 1949 (Comet 1949 a and/or 1949 d)[3]

Asteroids

Johnson is credited by the Minor Planet Center with the discovery of 18 asteroids:.[1]

1568 Aisleen21 August 1946list
1580 Betulia22 May 1950list
1585 Union7 September 1947list
1607 Mavis3 September 1950list
1609 Brenda10 July 1951list
1618 Dawn5 July 1948list
1623 Vivian9 August 1948list
1731 Smuts9 August 1948list
1760 Sandra10 April 1950list
1819 Laputa9 August 1948list
1885 Herero9 August 1948list
1922 Zulu25 April 1949list
2546 Libitina23 March 1950list
2651 Karen28 August 1949list
2718 Handley30 July 1951list
2829 Bobhope9 August 1948list
3184 Raab22 August 1949list
5038 Overbeek31 May 1948list

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 Organisation.

See also

References
  • Vermeulen, D.J. (2006) Living amongst the stars at the Johannesburg Observatory. Johannesburg: Chris van Rensburg Publications
  1. "Minor Planet Discoverers (by number)". Minor Planet Center. 2 April 2018. Retrieved 2 May 2018.
  2. "JPL Small-Body Database Browser: 48P/Johnson". Jet Propulsion Laboratory. Retrieved 2 May 2018.
  3. C. D. Shane (February 1952). "Report of the Donohoe Comet Medal Committee". Publications of the Astronomical Society of the Pacific. 64 (376): 39. Bibcode:1952PASP...64...39.. doi:10.1086/126418. Retrieved 2 May 2018.
  4. Johnson, Carolyn A. (2015). "Ernest Leonard Johnson (1891 - c.1977) - Genealogy". Geni.com. Retrieved 23 May 2019.
  5. "Johnson, Mr E L (astronomy)". S2A3 Biographical Database of Southern African Science. Retrieved 23 May 2019.
  6. R. G. Aitken (February 1936). "Report of the Comet Medal Committee with Awards of the Comet Medal". Publications of the Astronomical Society of the Pacific. 48 (281): 52. Bibcode:1936PASP...48...52.. doi:10.1086/124657.
  7. C. D. Shane (February 1949). "Report of the Comet Medal Committee". Publications of the Astronomical Society of the Pacific. 61 (358): 51. Bibcode:1949PASP...61...51.. doi:10.1086/126123.
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