John Louis Emil Dreyer

John Louis Emil Dreyer
John Louis Emil Dreyer.

John Louis Emil Dreyer (February 13, 1852 – September 14, 1926) was a Danish-Irish astronomer.[1][2]



He was born Johan Ludvig Emil Dreyer in Copenhagen: his father was the Danish Minister for War and the Navy. He was educated in Copenhagen but in 1874, at the age of 22, he went to Parsonstown, Ireland. There he worked as the assistant of Lord Rosse (the son and successor of the Lord Rosse who built the Leviathan of Parsonstown telescope).

During 1878 he moved to Dunsink, the site of the Trinity College Observatory of Dublin University to work for Robert Stawell Ball. In 1882 he relocated again, this time to Armagh Observatory, where he served as Director until his retirement in 1916. In 1885 he became a British citizen. In 1916 he and his wife Kate moved to Oxford where Dreyer worked on his 15 volume edition of the works of Tycho Brahe, the last volume of which was published after his death.

He won the Gold Medal of the Royal Astronomical Society in 1916 and served as the society's president from 1923 until 1925. He died on September 14, 1926.

A crater on the far side of the Moon is named after him.


His major contribution was the monumental New General Catalogue of Nebulae and Clusters of Stars (based on William Herschels Catalogue of Nebulae ), the catalogue numbers of which are still in use, as well as two supplementary Index Catalogues.

Dreyer was also a historian of astronomy. In 1890 he published a biography of Tycho Brahe, a noted astronomer from his native country, and in his later years he edited Tycho's publications and unpublished correspondence. History of the Planetary Systems from Thales to Kepler (1905), his survey of the history of astronomy, while dated in some respects, is still a good introduction to the subject. It is currently printed with the title A History of Astronomy from Thales to Kepler.


  1. ^ "obit. Dr. J. L. E. Dreyer". Nature 118 (2969): 454–455. 25 September 1926. Bibcode 1926Natur.118..454.. doi:10.1038/118454a0. 
  2. ^ "DREYER, John Louis Emil". Who's Who, 59: p. 508. 1907. 
  • Alexander, A. F. O'D., "Dreyer, Johann Louis Emil," Dictionary of Scientific Biography 4:185-186.
  • J. L. E. Dreyer, A History of Astronomy from Thales to Kepler, 2nd edition, Dover Publications, 1953.

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