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ANDREW AINSLIE COMMON. 18411903. 



Andrew Ainslie Common was born at Newcastle on August 7, 

 1841. He showed an interest in astronomy very early, for his brother, 

 writing of a time previous to 1851, remembers that "he was always 

 at the telescope " (an instrument which his mother had borrowed from 



Dr. Bates, of Morpeth) "Whenever I missed him I ran into 



the house and found him at the telescope." Owing to ill-health first, 

 and afterwards to the necessity for taking up business, his astronomical 

 enthusiasm lay dormant for some years after this, but in 1874 he had 

 a 5^-inch refractor mounted equatorially in a dome in London. After- 

 wards he moved to Baling, where he lived till his death ; he set up 

 larger instruments, joined the Royal Astronomical Society in 1876, 

 and from about that time, in spite of the claims of an active business 

 life, continued to work successfully at his favourite science, and to be 

 a prominent figure in astronomical circles. 



The earliest work of which there is any published record was on 

 the satellites of Saturn and Mars (" Mon. Not. R.A.S.," vol. 38, 

 p. 97), and characteristically included an improved method of getting 

 position-angles. Common was seldom content until he had suggested 

 some essential improvement on previous methods. There is a hint, 

 too, of dissatisfaction with the power of his instrument (an 18-inch 

 speculum, by Calver, which would have satisfied most of the 

 amateurs of the day), since the inner satellite of Mars could not 

 be seen; and in this we may trace the determination, already 

 formed, to have the larger instruments which made Common famous. 

 Little more than a year afterwards he published his ideas on the 

 subject of large telescopes, and it is noteworthy that his opinion was 

 courageously at variance with that of one of the first instrument 

 makers of the day (" Mon. Not. R. A.S.," vol. 39, p. 383, footnote). 

 Pie proceeded to order the well-known 3-foot mirror from Mr. Calver, 

 the mounting being his own design, and this instrument was a great 

 success. He could now see all the satellites of Mars and Saturn easily, 

 and corrected an error of about one and a-half hours in the ephemeris 

 of Mimas, which had remained undetected for some time, and had 

 been the cause of some curious records by other observers. But an 

 even greater success was in store ; he turned his attention to photo- 

 graphy, and took the first successful photograph of a nebula the 

 great nebula in Orion. For this he received the gold medal of the 

 Royal Astronomical Society in 1884. In presenting to the Society a 



