| 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. There are occasional meteorological observations. The volume contains astronomical sweeps numbered 610-917, with the dates, times and positions of each observation. Several sweeps might be undertaken in one night of observation. Herschel provides a commentary on many objects, more detailed in the case of interesting nebulae. Additional observations include comments on his equipment and its impact on the quality of the observations.
Herschel also states that 'I saw my Sister's [Caroline Herschel's] Comet with the 10 feet reflector...' on 18 October 1786. Visitors included Charles Blagden on 25 October 1786, who viewed 'the planetary Nebula in Andromeda...and my Sister's nebula...' The planetary nebula is shown to 'Dr Hebberdon and the Revd Mr Woolaston' on 26 October [William Heberden and Francis Wollaston]. On 13 February 1787 Herschel makes the famous observation of the M64 galaxy 'A very remarkable object...contains one lucid spot like a Star with a small black arch under it so that it gives one the idea of what is called a black eye, arising from fighting.' He shows this to Charles Blagden on 19 February 1787 after the memorandum 'This Evening I tried the 40 feet telescope for the first time on the Nebula in Orion. My apparatus not being ready I mounted within the tube and laying down in it saw the Nebula which was extremely bright...' A [later?] pencil note under adjusting equipment for observing Saturn on 19 August 1787 states 'Enceladus discovered this evening at 22h 18m'. Herschel tries a binocular eyeglass on his telescope on 18 October, noting the advantages of this. On 26-27 November 1787 he shows several objects to 'Messrs Cassini, Michain Le Genre & Carochet'. Other visitors include, on 11 March 1788, William Watson and William Marsden: 'Dr Watson and Mr Marsden saw the Satellites of the Georgian planet...They saw also the Volcano in the Moon...' Lord Palmerston is noted on 3 August 1788 and Jérôme de Lalande and [Edward?] Pigott visit on 5 and 6 August 1788 respectively.
The front cover is inscribed in ink: '(Originals) Sweeps. No.6. 610...917. From October 14, 1786. To March 23, 1789.' |