Bishops Meadowbank Observatory [BMO] (1861-1877)  Meadowbank House, Twickenham, established by George Bishop, Jnr., son of George Bishop (1785-1861). Upon the death of his father, he moved the 7-inch Dollond refractor and mount with the dome to a new larger observatory building at his riverside home in Twickenham. The move was forced due to the smoke and lights of London obscuring the southern horizon from Regents Park. John Hind moved there initially in order to continue his own observations, then George Talmage, a 24 year-old double star observer, returned until the Observatory was closed in 1877. He was assisted from 1868-74 by William E. Plummer who had been trained at the ROG. Plummer went on to be First Assistant at the new University of Oxford Observatory in 1875. The instruments and valuable library were given to The Royal Observatory (now Capodimontes Observatory), Naples (ILN 1869; Howard-Duff 1985, 25).
Count de Brühl’s Observatory [CdBO] (1790-1815), Harefield House, Harefield, established by Count de Brühl at his home. Equipped with a 2-foot Altazimuth Circle by Edward Troughton, London (ODNB; Howse 1986, 73).
Common’s Ealing Observatory [COE] (1876-1903), Ealing Common, established by Andrew Common in a shed in his garden, with an 18-inch silvered glass reflector (1876) – later disposed of to the the Duncombe Observatory, Leeds. In 1879 he designed a 36-inch mounting for a Calver mirror, using it for astrophotography. He replaced it in 1889 with a 60-inch reflector (ODNB).
De la Rue’s Cranford Observatory [LRCO] (1857-73), established by Warren de la Rue to house his 13-inch reflector, fitted a clock drive. He became a pioneering astro-photographer, designed the heliometer for Kew Observatory, and in 1873 when difficulties with his eyes compelled him to cease observing, he gave his reflector and the contents of his observatory to the new Oxford University Observatory (ODNB; Obit., MNRAS, 50 (1890), 155-64).
Minchenden School Observatory [MSOSL] (1936-1966), Southgate House, Southgate, London, established at the Grammar School by the Science master, Dr William Cameron Walker (1896-1978). An astronomy society had been instigated some years earlier with observations made from a raised platform that straggled a wall using small portable telescopes. The structure was extended to house a domed wooden building that housed a 5 ¼-inch refractor by Steinheil with a Cooke equatorial mount – originally at Osbourne House, IoW, on loan from the BAA. The observatory survived at least until the 1960s when telescope lens was stolen (1963) and fire nearly destroyed the structure in 1966 (‘Notes’, Obs, 59 (1936), 200; Holton 2018).
Water’s Observatory [WOH] (fl.1931), Durham Road, Harrow, established by Henry Hayden Waters at his home and equipped with a 5-inch Zeiss refracting telescope on loan from the BAA (Obit, MNRAS, 100 (1940), 264-5; Stroobant 1931).