Reino Antero Hirvonen

Reino Antero Hirvonen (1908–1989) was a famous Finnish physical geodesist, also well known for contributions in mathematical and astronomical geodesy.

He worked at first at the Finnish Geodetic Institute under W.A. Heiskanen on gravimetric geoid determination, publishing his dissertation The Continental Undulations of the Geoid[1] in 1934 on the determination of a global geoid model from only 4500 data points.

In 1950 he succeeded Heiskanen as Professor of Geodesy at the Helsinki University of Technology.

He also took an active interest in astronomy, acting from 1956 to 1964 as a vice president of the Finnish amateur astronomical society Ursa.

R.A. Hirvonen participated in the 1930s in the construction of triangulation towers, and measurements, for the first order triangulation of Finland. He also developed over the years many new mathematical algorithms for manual calculations (before the computer era), e.g., for calculating the Gauss-Krüger map projection.[2]

In 1947 he led a team of Finnish scientists to Brazil to measure the distance between South America and Africa. (T.J. Kukkamäki was the leader of the team sent to, then, Gold Coast, Africa.) They succeed with measurements using a method based on observing from points in Brazil and Africa. They used the solar eclipse happening that year, which was visible in both Africa and South America. Using long focus film cameras and the most accurate available radio time signals for the solar eclipse measurements, they were able to calculate the distance between Africa and South America to a higher accuracy than ever before: 141 m.[3]

1951–1952 and 1954–1955 Hirvonen lectured in the Department of Geodetic Science at The Ohio State University, in Columbus, Ohio (USA). He educated the students about navigation using the stars as reference points. Later it helped the USA to fly to the moon.