Common, Andrew Ansley

Andrew Ansley Common was born in 1841 into the family of surgeon Thomas Common, a renowned cataract specialist. The father died when Andrew was a child, after which the latter was forced to earn a living. From the 1860s to 1890, Andrew worked in London with his uncle's plumbing company, Matthew Hall and Company . Married in 1867. He died of heart failure on June 2, 1903.

Although Andrew Common worked in the field of plumbing, he is much more famous for his achievements in the field of astronomy, an interest in which he has shown since childhood. When Andrew was 10 years old, his mother borrowed a telescope, which the boy used with great interest from a local doctor, Dr. Bates ^[3] . Once again, he returned to astronomy at the age of 30, when he began using a 5.5-inch refractor to take photographs of the moon and planets.

In 1876, Commune became a member of the Royal Astronomical Society . Around the same time, he also moved to the Ealing district, at that time located outside the city limits of London, where he lived until the end of his life, having arranged an astronomical observatory in the garden of his house. To take photographs of the stars, Common began building a series of large using new silver-plated glass mirror technology. To produce the first telescope of his own design, in 1876, Kommon first tried to polish a 17-inch mirror, but then abandoned this idea and ordered an 18-inch (46 cm) mirror at the optical firm of George Culver of Chelmsford. In 1877 and 1878 he published several articles about his observations of the satellites of Mars and Saturn .

36-inch reflector

In 1879, Common acquired a new mirror with a diameter of 36 inches (910 mm) for installation in his new telescope. This telescope was used by Commons for further observations of the satellites of Mars and Saturn, and, in particular, showed that the ephemeris of Mimas’s orbit was inaccurate. Using a 36-inch telescope, Common also received a photograph of the 1881 great comet, . The most famous work of Common with this telescope is to obtain photographs of the Orion nebula in the period 1880-1884. His photograph of the 1883 nebula for the first time showed the ability of a photographic plate to capture images of stars and other objects inaccessible to the naked eye. Common commented on his own photographs: “although some details are lost in magnification, it remains enough to say that we are approaching the time when the photograph will give us the means to record the unique appearance of the nebula and its parts of different brightness - better than the most thorough manual drawing ".

Photographs of the Orion Nebula were awarded the Gold Medal of the Royal Astronomical Society in 1884. Subsequently, Common sold the 36-inch reflector to the astronomer and politician , who in turn transferred the instrument in 1895 to the Lick Observatory in the United States, where the instrument after the politician.

60-inch reflector

In 1885, Common began creating a 60-inch (152 cm) reflector. He decided to buy an unprocessed glass billet and independently make grinding and polishing. The first mirror he made was of poor quality, and in 1890, Common set to manufacture the second mirror. In the course of the work, Common decided to change the design of the telescope to for safer use. To prevent a hole in the 60-inch , Common set a diagonal flat mirror in front of him, which brought the image into focus on the underside of the telescope. Common was not satisfied with the operation of the telescope of this configuration. After the death of Commons, a telescope with two 60-inch mirrors and other secondary optics was acquired by the Harvard College Observatory and installed in it ^[4] . In 1933 ^{[5] the} main mirror of this telescope was reconstructed and mounted on a new basis, after which it was transferred to the Boyden Observatory in South Africa - a subsidiary of the Harvard Observatory, where it is currently part of the 1.5-meter Boyden-UFS reflector (also called "60-inch Rockefeller").

Common retired from the plumbing company Matthew Hall and Company in 1890, after which he devoted himself entirely to optical design, proving himself a pioneer in the production of large optical mirrors. Most of the time he devoted to designing telescopic and optical sights for the Royal Navy and artillery. Captain (later Admiral) Percy Scott , one of the Royal Navy ’s leading artillery officers, said in 1902 that Commune "... made [that is," designed "] a telescope sight that, when used properly, quadruples the efficiency of warships" .

In the years 1895-1897, Andrew Common was president of the Royal Astronomical Society ^[6] .

During the Second Boer War, Common developed an experimental telescopic sight for the Lee Enfield rifle on a removable offset mount that anticipates the design of many subsequent gun sights.

• Obituary Notices: Fellows: - Common, Andrew Ainslie // English Monthly Notices of the Royal Astronomical Society : journal. - Oxford University Press , 1904. - Vol. 64 . - P. 274-278 . - DOI : 10.1093 / mnras / 64.4.274 . - .
• Turner, HH Obituary: Andrew Ainslie Common (English) // The Observatory . - 1903. - Vol. 26 . - P. 304-308 . - .
• Gingerich, Owen. The First Photograph of a Nebula (Eng.) // Sky and Telescope : magazine. - 1980. - No. November . - P. 364-366 .

• ' The Common Man' Andrew Ainslie Common (1841-1903)
• Portrait of Andrew Ainslie Common from the Lick Observatory Records Digital Archive, UC Santa Cruz Library's Digital Collections