Karl Friedrich Küstner

Karl Friedrich Küstner ( born August 22, 1856 in Görlitz, † October 15, 1936 in Mehlem ( today part of Bonn) was astronomy professor in Bonn and is considered the discoverer of the polar motion of the earth.

Life

Küstner worked as an Observer at the Hamburg Observatory, and since 1884 at the Berlin Observatory. From 1891 to 1925 he was director of the Royal Observatory of Bonn. As such, he was responsible for the acquisition of a refractor with a focal length of 5 m and initiated the transition from visual to photographic astronomy. With the refractor he recorded about 600 photographic plates of star clusters in the years 1900-1922. Due to their height quality, the plates were even decades later as the basis for the Bonn self-movement studies.

Even before his time in Bonn presented Küstner 1885-1888 found that in longer series of measurements of latitude ( latitude) of a small periodic influence of about 0.3 " (10 meters) is revealed. , He makes only about one- millionth of the earth's radius from, was so then, on the border of detectability. Based on current knowledge, the polar motion proceeds in the form of a spiral vibration amplitude of 5-10 m and about 430 days ( Chandler period).

Due to the discovery Küstners, which was further investigated by Seth Carlo Chandler et al and Richard Schumann, astronomers established the International Latitude Service with five world observatories at 39 ° latitude (later International Polar Motion Service ( IPMS) and the International Earth Rotation and Reference Systems Service ( IERS, International Earth Rotation ).

Küstner established in 1905 solar parallax and the aberration constant from spectrographic measurements. He also created in 1908 a star catalog with 10,663 exact Sternörtern.

In 1910 he was awarded the Gold Medal of the Royal Astronomical Society.