Olaus Christensen Roemer

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Roemer, Olaus Christensen


Born Sept. 25, 1644, in Aarhaus; died Sept. 19, 1710, in Copenhagen. Danish astronomer. Professor at the University of Copenhagen (from 1681).

In 1675, Roemer determined the speed of light from observations of occultations of the satellites of Jupiter. He also invented several astronomical instruments, including the meridian circle and the equatorial telescope with an hour circle and a declination circle. With these instruments, he determined the declination and right ascension of more than 1,000 stars.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.