On February 13, 1852, Danish-Irish astronomer John Louis Emil Dreyer was born. Dreyer’s 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 today.
John Louis Emil Dreyer was the son of Lieutenant General John Christopher Dreyer, back then the Danish Minister for War and the Navy. From early age, Dreyer became enthusiastic about astronomy and also visited Hans Schjellerup at the Copenhagen observatory. John Dreyer was educated in Copenhagen but moved to Parsonstown, Ireland at the age of 22. There, Dreyer became assistant to the amateur astronomer Lawrence Parsons.
In 1878, John Dreyer moved to Dunsink, the site of the Trinity College Observatory of Dublin University to work for the Irish astronomer and founder of the screw theory Robert Stawell Ball. Next, Dreyer began working at the Armagh Observatory, where he was appointed Director until his retirement in 1916.
To John Dreyer’s major contributions belongs the New General Catalogue of Nebulae and Clusters of Stars. It was based on William Herschels Catalogue of Nebulae. Its catalogue numbers as well as two supplementary Index Catalogues are still in use. John Dreyer had already published a supplement to Herschel‘s General Catalogue with around 1000 new objects. When he suggested building another supplement to the General Catalogue, the Royal Astronomical Society asked Dreyer to compile a new version instead.
When Dreyer assembled the New General Catalogue of Nebulae and Clusters of Stars, he faced a series of contradicting reports. Dreyer checked some of these himself, but still, the catalogue contained several errors. Fortunately, Dreyer was very careful in his referencing which allowed future astronomers to review the original references and publish corrections to the original NGC.
In 1916 he and his wife Kate moved to Oxford where Dreyer worked on his 15 volume edition of the works of Tycho Brahe, Opera Omnia the last volume of which was published after his death ion 1926.
At yovisto academic video search you can learn more about Start Dust in a lecture by Carolin Crawford at Gresham College.
References and Further Reading:
-  John Dreyer at the Royal Astronomical Society
-  John Dreyer Short Biography at Armagh Observatory
-  John Dreyer Biography at LCAS
-  Tycho Brahe – The Man with the Golden Nose, SciHi Blog, December 14, 2012.
-  Sir William Herschel and the Discovery of Uranus, SciHi Blog, March 13, 2014.
-  John Dreyer at Wikidata