Hisashi Kimura Japanese astronomer. Date of Birth: 10.09.1870 Country: Japan

1. Early Life and Education
2. Observational Astronomy
3. Research on Earth's Polar Motion and Latitude Variations
4. Honors and Recognitions

Early Life and Education

Hisayoshi Kimura was born in Kanazawa, Ishikawa Prefecture, Japan. In 1892, he graduated from the University of Tokyo.

Observational Astronomy

In 1896 and 1897, Kimura participated in observations of total solar eclipses. He established and directed the International Latitude Observatory in Mizusawa (now the city of Oshu) from 1899 to 1941. From 1922 to 1936, he served as Head of the Central Bureau of the International Latitude Service.

Research on Earth's Polar Motion and Latitude Variations

Kimura's primary research interest was the study of Earth's polar motion and latitude variations. In 1902, while analyzing data from the International Latitude Service, he proposed adding an additional term to the formula used to determine the coordinates of Earth's pole. This term, known as Kimura's term or the z-term, is constant across all observation stations and is independent of their coordinates. Its origin remains uncertain, with various theories including errors in stellar declinations.

Honors and Recognitions

Kimura was elected to the Japan Academy in 1925. He served as President of Commission 19 on "Study of Latitude Variations" of the International Astronomical Union from 1919 to 1935. He was awarded the Gold Medal of the Royal Astronomical Society in 1936 and the Order of Culture in 1937, one of its first recipients. A lunar crater and asteroid 6233 are named in his honor.