Nebulae sweep book of William Herschel Records of telescopic sweeps of the night sky, made at Slough, Berkshire, England, generally with a reflecting telescope of 20 feet diameter. The sweeps were made to observe nebulae, with notes on stars and other objects of interest. The volume contains astronomical sweeps numbered 142-191, with the dates and times of each observation. Several sweeps might be undertaken in one night of observation. Herschel provides a commentary on many objects and these are occasionally supplemented by later pencil inscriptions: for example, on sweep 170, March 14 1784, he sees 'a beautiful cluster of st. one of the most beautiful objects I have seen', to which has been appended, in pencil, 'M.53' [Messier 53, a globular cluster in Coma Berenices]. A note on the inside front cover states that: 'Sw 187 used tenths of minutes'. The volume contains a loosely inserted scrap with a manuscript list of observations [extracted from Philosophical Transactions?] headed '1800', but in a later script. The front cover is inscribed in ink: 'Sweeps. No.2. 142...191. From February 13, 1784. To April....13, 1784.' 13 February-13 April 1784