Nebulae sweep book of William Herschel

Description

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 191-353, with the dates, times and positions of each observation. Several sweeps might be undertaken in one night of observation. Notes on bells indicate the use of Alexander Herschel's bell machine, notifying William Herschel that the limits of the two degree field of view had been reached. Herschel provides a commentary on many objects, more detailed in the case of interesting nebulae. The volume concludes with a table used for variations in 1784.

A note on the inside front cover states: 'NB The line down the side denotes that this Sweep, the next day after having been made, was transcribed into the books called fixed stars. The continuation of this Sweep is on page 581. Explanation f or p S or n Stand for preceding or following a star; or for north or south of the Star.'.

The volume contains a loosely inserted scrap with later manuscript notes on a copy circular, c.1900.

The front cover is inscribed in ink: 'Sweeps. No.3. 191...353. From April...13, 1784. To January...6, 1785.'

Reference number

MS/272/3

Earliest possible date

13 April 1784-6 January 1785

Physical description

On paper, sewn into a pasteboard cover.

Page extent

304 pages.

Format

Manuscript