Cooper, Edward Joshua

Edward Joshua Cooper (1798-1863)

Astronomer

Edward Joshua Cooper was born in Dublin in May 1798.   He established a well-equipped private observatory on his estate at Markree Castle in Co. Sligo. Notable achievements at Markree were the mapping of over 60,000 stars around the ecliptic and the discovery of the minor planet Metis in 1848. His mother is said to have inspired his early interest in astronomy which was reinforced by visits to Armagh Observatory when he was a schoolboy in Armagh .   He proceeded to Eton and Christ Church Oxford but left after only two years without taking his degree.

Cooper travelled extensively in Italy and then in Egypt where he employed a landscape artist to record the scenery. On his return to Ireland , he married Sophia (Sophie) L'Estrange who bore him a son who lived only a few days and she, herself, died shortly afterwards.   He later married Sarah Frances Wynne who bore him five daughters.

During 1824 and 1825 Cooper resumed his travels, visiting Denmark , Sweden and Norway . In 1824 he also started to make meteorological observations at Markree. Owing to his frequent absence, the initial records were somewhat irregular but from 1833 they were as good as any made elsewhere in Ireland at that time.

On the death of his father in 1830, Cooper became manager of the Markree estate and he resolved to establish an astronomical observatory. In 1831 he purchased from Cauchoix in Paris a lens of 13.3-inch aperture and 25-feet focal length, the largest then in existence.   News of this purchase soon reached Thomas Romney Robinson, director of Armagh Observatory, and a cordial friendship ensued. Robinson persuaded Cooper to order a tube and equatorial mounting from Thomas Grubb in Dublin ; this was Grubb's first major commission. The telescope was erected in April 1834. Cooper also purchased a 5-foot transit instrument, a meridian circle 3-feet in diameter with a 7-inch objective and a 3-inch comet seeker. In 1851 Markree was authoritatively described as 'undoubtedly the most richly furnished of private observatories'.

In March 1842 Cooper appointed Andrew Graham (1815-1908) as an assistant.   Graham found accurate positions of 50 telescopic stars within 2˚ of the pole. In 1844 and 1845 Cooper and Graham toured France , Germany and Italy taking the great refractor with them.  

In 1848 Graham discovered the ninth minor planet and it was named 'Metis'. In order to facilitate the study of minor planets, Cooper initiated a programme of observing stars along the ecliptic. The results gave the approximate positions of 60,066 stars within three degrees of the ecliptic, only 8,965 of which were already known. For this important contribution, the Royal Irish Academy awarded Cooper its Cunningham gold medal. He had been a member of the Academy from 1832 and was elected a fellow of the Royal Society in June 1853.   He was the MP for Co. Sligo from 1830 to 1841 and again from 1857 to 1859. He was a kind and good landlord who combined a pleasant disposition with his varied accomplishments. Cooper died in 1863.

Reference: Charles Mollan. 2007. It’s Part of What We Are. Royal Dublin Society.