Telegraphic Determinations of the Difference of Longitude between, Karachi, Avanashi, Roorkee, Pondicherry, Colombo, Jaffna, Muddapur and Singapore, and the Government Observatory, Madras.

Madras: Printed at the Lawrence Asylum Press by W. H. Moore (small press ticket rear pastedown), 1884. Illustrated by tables. First edition. Presentation plate front pastedown "By order of the Right Honorable the Governor in Council at Madras to The Dudley Observatory, Albany" with their bookplate. Navy pebble cloth, gilt stamped spine (Telegraphic Longitude Determinations in India) also title of introductory remarks. Demy 4to (28cm). pp. 82. Very Good/No jacket, as issued. Lightly sunned spine (looking a bit green), two barely bumped corners, specks and spots of soil/stain, one tiny top-edge tear pp. 79-80. Pogson was the fifth Governor astronomer (1861-91) of the Madras Observatory since 1792 (Topping, Goldingham, Taylor, Jacob) and had proposed the survey since the end of 1861. Results were conjointly made in 1870 on with Mons. G. Fleuriais (Lieutenant de Vaisseau, en Mission Scientifique a Pondicherry), letter of 12/1869 in introduction. (As Admiral, Fleuriais would later develop the gyroscopic horizon in 1884). Chronological results for Madras Observatory East of Greenwich: 5h 20m 57.2s (Goldingham's of 1787-1815 and 1817-26 mean value .4s); 5h 21m 3.77s (T.G. Taylor's of 1831, adopted by Nautical Almanac 1835-61); 5h 20m 57.2s (Taylor second of 1833-44, Nautical Almanac 1862-82 by combination result of Transit of Venus Expedition 1874, Great Trigonometrical Survey India 1876&7 and other between Aden, Bombay, Madras & Suez); 5h 20m 59.40s (Pogson & Fleuriais appearing here). The observatory would move to Mirzipur in 1947 to be situated exactly 5h and 30m from Greenwich thus establishing IST which Indians refer to as 'Indian Stretchable Time' as daylight savings is not observed. Pogson wrote a 51,1101 star catalog (1862-87), Observations of 31 Variable Stars (1908) which Turner finished after his death, formulated the stellar magnitude system known as the Pogson ratio (2.512), discovered 21 variable stars, 8 asteroids. Pogson's May 16, 1886 discovery of 87 Sylvia would later be named by Marchis et al (2005) the first triple asteroid (with twin moons Romulus and Remus). The Pogson Crater (Moon) and Asteroid 1830 Pogson are named for him..