In June 1882, at 30 years of age, John Dreyer was appointed Director of Armagh Observatory following the death of Thomas Romney Robinson, who had held the post for a lengthy 59 years. He was the first non-Irishman and non-cleric to hold the position. Dreyer is best remembered for creating the New General Catalogue of Nebulae and Star Clusters (NGC) published in 1888. He was a prolific writer and researcher and is noted for his contributions to the history of astronomy, especially for his biography of Tycho Brahe.

Johan Ludvig Emil Dreyer, later changed to John Louis Emil Dreyer, was born on 13 February 1852 in Copenhagen, Denmark.  There was a tradition of military careers in his family but he chose a different life path becoming an astronomer of international repute. He was a bright young boy who excelled in languages, history and science at school. The seed of his future career was sown when, at 14 years, he got his hands on a book about Tycho Brahe (1546 – 1601) who seems to have led a very interesting life. Around this time he was a frequent visitor to Copenhagen Observatory where he was strongly influenced by Professor Schjellerup  (who in my opinion put to bed a long time ago the argument about ‘red’ Sirius ).

image of copenhagen observatory

John Dreyer visited Copenhagen Observatory on a regular basis in his youth. (Image credit: Wikipedia)


From 1869 to 1873 Dreyer attended the University of Copenhagen where he studied logic, astronomy and mathematics. He attended the lectures of Professor d’Arrest who gave him support and encouragement in his chosen field. He published his first scientific paper in 1872 while still a student, ‘On the Orbit of the First Comet of 1870’. He also published some popular articles on astronomy and a review of a book about his hero Tycho Brahe.  While working at Copenhagen Observatory he wrote an essay on the question of personal errors in observations and for this he received a gold medal from the university.


image of Telescope and sinead mcnicholl

John Dreyer had access to the largest telescope in the world when he worked at Birr. Today it is being restored. (Image Credit: Sinead McNicholl)

At 22 years of age John Dryer left his homeland in August 1874 to take up a position as assistant astronomer at Birr Castle in Ireland. There he assisted Lawrence Parsons, the Fourth Earl of Rosse, and the son of William Parsons, of Crab Nebula fame. At Birr he had access to the largest telescope of the day, the 72-inch reflector known as the ‘Leviathan’. His main duties consisted of observing and cataloguing nebulae and star clusters. He published many papers on his work and in 1877 he published a supplement to Sir John Herschel’s General Catalogue of Nebulae and Clusters.

But it wasn’t all work and no play for John. While at Birr he found the time to meet and become engaged to Katherine Hannah Tuthill, from Kilmore, County Limerick. They got married on 11 November 1875. Their first son Jack was born on Christmas Eve 1876. Jack’s brother, Frederic Charles*, was born just over a year later on 8 January 1878. John Dreyer arrived in Birr a single man. He left it four years later, August 1878, for Dunsink Observatory, Dublin, with his wife Kate and two baby sons. It cannot have been an easy move though in those days it was probably his wife who shouldered most of the responsibility for the young children.


Image of Dunsink observatory

Dunsink Observatory was home to the Dreyer family for four years. (Image credit: Wikipedia)


Dreyer spent another four years at Dunsink where he worked as assistant to Robert Stawell Ball. He continued to catalogue non-stellar objects…. Along with his life-long friend Ralph Copeland he edited a magazine called Copernicus which was an early attempt at international communication among astronomers. Though well received the project was abandoned after three years. But it does show that Dreyer firmly believed in the importance of cooperation and sharing information in astronomy. Family life was getting more hectic at the Dreyers’ with the arrival of a daughter, Alice Beatrice, born on 28 October 1879. John and Kate must have had their hands full with three children under three years.


image of Armagh Obs_1883

Armagh Observatory in 1883. (Credit Image: courtesy of Armagh Observatory)


John Dreyer and family moved again in August 1882. On 16 June he was appointed the new Director of Armagh Observatory following the death of Thomas Romney Robinson.  Due to the need for refurbishment he didn’t move immediately. They arrived in Armagh at the end of the summer of that year and were to remain for the next 34 years. Kate was expecting their fourth child at this stage and George Villiers was born on 27 February 1883. Two more children were born at Armagh, William Lloyd on 17 May 1885 and Margaret Ida on 5 September 1887. Tragically these two younger children died.  Margaret Ida died in October 1888; she was only 13 months. Six months later in April 1889 her older brother William Lloyd died; he was just 4 years old. Both children are buried in St Mark’s Parish Church graveyard.  This must have been an awful time for the Dreyer family.

When John Dreyer took up the directorship of Armagh Observatory things were not in great shape. Money was scarce and the telescopes were not the most up to date available.  Thanks to his persuasive powers he secured funding of £2,000 for a new 10-inch Grubb refractor with a focal ratio of 1:12. This was most suitable for observing nebulae which was his passion. It was ready for use in July 1885.

One of the first astronomical events that Dreyer would have observed in his new position would have been the transit of Venus on 6 December 1882. To observe this rare phenomenon he used the 15-inch Grubb reflector (with some suitable adjustments) which had been erected in 1835.


image of transit of venus

This image shows the transit of Venus on 6 June 2012. (Image credit: Terence Murtagh)


On arrival at Armagh Dreyer set about reducing and collating the observations made by his predecessor Dr Robinson. The result was the Second Armagh Catalogue published in 1886. This contained many observations made by himself in 1882 and 1883. In 1888 his New General Catalogue of Nebulae and Star Clusters (the famous NGC) was published. He created two supplementary works: the Index Catalogues which were published in 1895 and 1908.  His work is recognized world-wide as the standard catalogue for nebulae.  He wrote various articles about nebulae and also devoted time to another subject that was dear to his heart, the history of astronomy. He has made major contributions to the literature on this subject.


image of Dreyer as a young man

John Dreyer was a young man when he became Director of Armagh Observatory. (Image credit: courtesy of Armagh Observatory)


In 1883 he wrote a Historical Account of the Armagh Observatory. He wrote a biography on his fellow countryman, Tycho Brahe, the great astronomer. This work entitled Tycho Brahe, a Picture of Scientific Life and Work in the Sixteenth Century was published in 1890 in Edinburgh. The 405 page book is still a classic to this day. In 1906 another major historical study, the History of Planetary Systems from Thales to Kepler, was published in Cambridge.

When the Royal Society and the Royal Astronomical Society decided that an edition of the complete works of William Herschel should be produced they picked John Dreyer for the job.  This important work,The Scientific Papers of Sir William Herschel, consisting of two volumes (1441 pages) was published in 1912.  It also contained a biography of Herschel written by Dreyer using his own unpublished material. In 1916 the Royal Astronomical Society awarded John Dreyer their Gold Medal for his contributions to the world of science. It was a well deserved honour. The same year he (at 64 years) and his wife Kate left Armagh for Oxford.

In Oxford he had access to the famous Bodleian Library.  He continued a project that began in Armagh namely the production of an edition of the complete work of Tycho Brahe. The final work comprised 15 volumes, eight of which were published in Armagh and the rest in Oxford, three posthumously. Along with Professor Turner he edited a History of the Royal Astronomical Society which was published in 1923. He received another honour that year being elected President of the RAC. This was a sad time for John Dreyer. His beloved wife, Kate, had just passed away. They had been married for 49 years. Dreyer was now 72 years of age. He outlived his wife by two years and passed away peacefully in Oxford on 14 September 1926. He was 74 years old.

*Naval history buffs will recognise this little chap as the future Admiral Sir Frederic Charles Dreyer, GBE, KCB who devised the “Dreyer Tables” by the Royal Navy in both World Wars used to lay naval gunfire -ED

(Article by Mary Bulman, Education Support Officer)

1 Comment

Explorers of the Galaxy (Part 1) | Astronotes · March 11, 2016 at 14:37

[…] is also catalogued as NGC 5194 in the “New General Catalogue”, published by Dreyer in 1888 based on measurements made at Armagh Observatory. The NGC catalogue became the principal […]

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