A wooden box labelled 'HERSCHEL EYEPIECES' containing 10 complete eyepiece mounts (all without lenses), three incomplete mounts and a pill box labelled 'Apertures and carrying plates' and containing a number of small stamped plates of thin brass similar to those used for mounting the lenses in some eyepieces.

Of the complete eyepieces five have a medium thread, three a small thread and two a very small thread. Also contained within this set is a double brass adapter (with a large thread) to take eyepieces of medium and small thread. There is also a brass screw-cap for an eye-tube, with a central hole for centering and adjusting mirrors.

William Herschel's eyepieces, made for him by his younger brother Alexander are outstanding because of their magnifying power which was exceptionally high for the time. In his 'Account of a Comet', read to the Royal Society in April 1781 (the comet in question was later confirmed to be Uranus) he referred to having 'ready at hand the several magnifiers of 227, 932, 1536, 2010, &c'. At the time a power of 270 was considered excellent, and his audiences disbelief at his claims of magnification was a serious hurdle in getting his discovery recognised.