Michiel Daniel Overbeek (15 September 1920 in

Ermelo, Mpumalanga Ermelo () is the educational, industrial and commercial town of the 7,750 km2 Gert Sibande District Municipality in Mpumalanga province, Republic of South Africa. It is both a mixed agriculture and mining region. It is located 210 km east ...

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

– 19 July 2001 in

Johannesburg Johannesburg ( , , ; Zulu and xh, eGoli ), colloquially known as Jozi, Joburg, or "The City of Gold", is the largest city in South Africa, classified as a megacity, and is one of the 100 largest urban areas in the world. According to Demo ...

), also known as Danie Overbeek, was a South African

amateur astronomer Amateur astronomy is a hobby where participants enjoy observing or imaging celestial objects in the sky using the unaided eye, binoculars, or telescopes. Even though scientific research may not be their primary goal, some amateur astronomers m ...

and one of the most prolific

variable star A variable star is a star whose brightness as seen from Earth (its apparent magnitude) changes with time. This variation may be caused by a change in emitted light or by something partly blocking the light, so variable stars are classified as ...

observers.

Life

He studied in a Mining and Metallurgy program at the

University of the Witwatersrand The University of the Witwatersrand, Johannesburg (), is a multi-campus South African Public university, public research university situated in the northern areas of central Johannesburg. It is more commonly known as Wits University or Wits ( o ...

. During the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

he served in the

South African Air Force "Through hardships to the stars" , colours = , colours_label = , march = , mascot = , anniversaries = , equipment ...

and was awarded the

Africa Star The Africa Star is a military campaign medal, instituted by the United Kingdom on 8 July 1943 for award to British and Commonwealth forces who served in North Africa between 10 June 1940 and 12 May 1943 during the Second World War. Three clasp ...

and

mentioned in Dispatches To be mentioned in dispatches (or despatches, MiD) describes a member of the armed forces whose name appears in an official report written by a superior officer and sent to the high command, in which their gallant or meritorious action in the face ...

. After the war he worked for

South African Airways South African Airways (SAA) is the flag carrier airline of South Africa. Founded in 1934, the airline is headquartered in Airways Park at O. R. Tambo International Airport in Johannesburg and operated a hub-and-spoke network, serving ten destin ...

and

South African Railways Transnet Freight Rail is a South African rail transport company, formerly known as Spoornet. It was part of the South African Railways and Harbours Administration, a state-controlled organisation that employed hundreds of thousands of people ...

. In 1945 he married Jean Mary Preddy, with whom he had four children. She died in 1985.

Astronomy

Daniel Overbeek's serious interest in

astronomy Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...

dates back to 1951, when he started observing

occultation An occultation is an event that occurs when one object is hidden from the observer by another object that passes between them. The term is often used in astronomy, but can also refer to any situation in which an object in the foreground blocks ...

s and variable stars. In 1958 he earned a

B.Sc. A Bachelor of Science (BS, BSc, SB, or ScB; from the Latin ') is a bachelor's degree awarded for programs that generally last three to five years. The first university to admit a student to the degree of Bachelor of Science was the University of ...

degree in

mathematics Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...

and astronomy from the

University of South Africa The University of South Africa (UNISA), known colloquially as Unisa, is the largest university system in South Africa by enrollment. It attracts a third of all higher education students in South Africa. Through various colleges and affiliates, U ...

. In his life he contributed 287,240 observations to the

American Association of Variable Star Observers The American Association of Variable Star Observers (AAVSO) is an international nonprofit organization, founded in 1911, focused on coordinating, analyzing, publishing, and archiving variable star observations made largely by amateur astronomers. ...

(AAVSO) International Database, becoming the most prolific AAVSO contributor. In 1998 he became the first amateur astronomer who detected

supernova A supernova is a powerful and luminous explosion of a star. It has the plural form supernovae or supernovas, and is abbreviated SN or SNe. This transient astronomical event occurs during the last evolutionary stages of a massive star or when ...

gamma ray burst In gamma-ray astronomy, gamma-ray bursts (GRBs) are immensely energetic explosions that have been observed in distant galaxies. They are the most energetic and luminous electromagnetic events since the Big Bang. Bursts can last from ten milli ...

effects. He also monitored

Earth's magnetic field Earth's magnetic field, also known as the geomagnetic field, is the magnetic field that extends from Earth's interior out into space, where it interacts with the solar wind, a stream of charged particles emanating from the Sun. The magnetic f ...

and

seismic Seismology (; from Ancient Greek σεισμός (''seismós'') meaning "earthquake" and -λογία (''-logía'') meaning "study of") is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other ...

activity with a

magnetometer A magnetometer is a device that measures magnetic field or magnetic dipole moment. Different types of magnetometers measure the direction, strength, or relative change of a magnetic field at a particular location. A compass is one such device, o ...

and a

seismograph A seismometer is an instrument that responds to ground noises and shaking such as caused by earthquakes, volcanic eruptions, and explosions. They are usually combined with a timing device and a recording device to form a seismograph. The output ...

he had built, and observed sudden ionospheric disturbance.

Acknowledgement

In 1956 Daniel Overbeek became the chairman of the Transvaal Centre 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 ...

(ASSA). He was elected the president of the ASSA twice: in 1961 and 1999. In 1984 he was awarded the Gill Medal, the highest ASSA honour. The American Association of Variable Star Observers awarded him with the Merit Award in 1986 and the Director's Award in 1994. He was also a multiple AAVSO Observer awardee: in 1994 for making 100,000 variable star observations, in 1997 for 200,000 and in 1999 for 250,000 observations. In 1995 he received the Christos Papadopoulos Trophy of the Transvaal Centre of the ASSA. He also won the Amateur Achievement Award of the Astronomical Society of the Pacific in 1996. The

Mars-crosser asteroid A Mars-crossing asteroid (MCA, also Mars-crosser, MC) is an asteroid whose orbit crosses that of Mars. Some Mars-crossers numbered below 100000 are listed here. They include the two numbered Mars trojans 5261 Eureka and . Many databases, for in ...

5038 Overbeek was named in his honour in 2000.

References

{{DEFAULTSORT:Overbeek, Michiel Daniel 1920 births 2001 deaths People from Ermelo, Mpumalanga Afrikaner people South African people of Dutch descent South African astronomers Amateur astronomers 20th-century astronomers South African World War II pilots University of the Witwatersrand alumni