23 June

1901: On 23 June 1901, Otto Heckmann was born.

Heckmann was a German astronomer noted for measuring stellar positions and his studies of relativity and cosmology. He also made notable contributions to statistical mechanics.

Heckmann organised an international programme to photograph and chart the positions of the stars in the Northern Hemisphere, which led to the publication in 1975 of the third German Astronomical Society catalogue, the Astronomische Gesellschaft Katalog (AGK3).