Some Comments by Caroline Herschel on the use of the 40ft Telescope

“‘On the Power of Penetrating into Space’: The Telescopes of William Herschel”, Journal for the history of astronomy, vii (1976), 75–108.

“The great end in view is to increase what I have called the power of extending into space”, Herschel to Sir Banks Joseph , 9 August 1785, in Aspinall , op. cit. (ref. 7), i, 179.

Mus Br. . ms 3761 ff60r-61v (April 1827).

That is, in Caroline's second biographical memorandum which covered the years 1772 to 1788 and which she had just despatched to her nephew.

Caroline was thoroughly unhappy and very lonely in her self-imposed exile in Hanover where she strongly disliked the family of her brother Dietrich (see Egerton ms 3761 ff 67v and 69r). She was however very tender of any public remarks which could reflect upon her family's reputation. It was for this reason she so often insisted to John that her remarks and her autobiography were only for his eyes, and even suppressed some passages in the autobiography before sending it to him.

Caroline here added her own footnote in the form of a P.S.: “I must say a few words by way of apology for the good king and ascribe the close bargens which were made between Him and my Brother to the shaby mean spirited advisers who were undoubtedly consulted on such occasions…. NB Sr Banks J. remained a sincere well meaning friend to the last.”

Correspondence about the 40ft telescope between Herschel and Banks together with statements of the expenses are printed in Aspinall A. , The later correspondence of George III (5 vols, London, 1952–70), letters 236, 369, 379, 432, 570. The sums for which Herschel rendered 23 receipts from February 1786 to July 1790 (including his salary) totalled £2947. 10s. Od. His original estimate had been £1395 with £150 per annum maintenance.

The ruin of her brother's health by his astronomical exertions made a deep impression upon Caroline who in her letters from Hanover is constantly asking for assurances of her correspondents' health. In particular when John was beginning some sweeps with his father's instruments in 1826 she not only sent many hints but also a long detailed warning against over-taxing his strength as his father had done (Caroline to John Herschel, 1 February 1826, Egerton ms 3761 f45r).

I.e. Sidus Georgium as Herschel named Uranus, two satellites of which were detected in 1787.

The polar distance clock and an astronomical regulator by John Shelton were kept together in the hut where Caroline worked ( Bennett , op. cit., 91). The regulator, which remains in the possession of Herschel's descendants, was given to Herschel in 1786 by Alexander Aubert who states that “The Regulator was Skelton's own and which he made for himself” (Aubert to Herschel, 19 October 1786, printed in Constance Lubbock A. , The Herschel chronicle, the life-story of William Herschel and his sister Caroline Herschel (Cambridge, 1933), 180).