This 6ft 7inch equatorially mounted refractor is named after the donor of its object glass, Rev Richard Sheepshanks (1794-1855). In 1838 it was mounted in the South (or Sheepshanks) Dome, east of the Circle Room, which was built originally to house the Shuckburgh Equatorial telescope (now at the Science Museum). It was used to observe comets, occultations, double-stars (until about 1870) and make planetary measurements.

The object glass was made by R.A. Cauchoix and and the mounting was ordered by George Biddle Airy, the seventh Astronomer Royal, from Thomas Grubb. The first observations made with this telescope were of Encke's comet on 29 Oct 1838. In 1839 a double-image micrometer was acquired. In 1888 the whole telescope was dismounted, cleaned, remounted and adapted for stellar photography, although it was seldom used for this purpose. In 1890 a comet eyepiece was acquired. In 1914 the object glass was removed and used for the eclipse of August 1914.

In 1949-50 the telescope was used to make some solar observations after the removal of the photoheliograph to Herstmonceux. In 1952 the telescope was dismantled again, reconditioned and re-erected in a reconditioned dome. In 1963 it moved to Altazimuth Pavilion and handed over to the National Maritime Museum. In 1964 new finder telescope was added by Wildey. It was removed from the Altazimuth Pavilion in the early 1980s and is now in the Museum's stores.

The telescope consists of a square wooden barrel tapering to round ends with fittings and mountings made of grey-painted iron. There are two fine adjustment handles and a small refracting telescope on the underside of the eye end for sighting. The aperture of the Couchoix object glass is 165mm and its focal length 1879.6mm. In 1964 the object glass was replaced by Mr Wildey of the BAA who also recommended the purchase of a finderscope and some additional though contemporary eyepieces to allow the telescope to be used for public viewing. In 1965 discussion continued, this time with a view to having a device fitted allowing photographs to be taken through the telescope.

Described in Greenwich Observations 1838 as being 'similar in general form to that of the Dorpat telescope.' The cast-iron cradle mounting is designed to fit onto a stone pier of breadth 406.4mm and length 1625.6mm. The stone pier is aligned lengthways along a north-south line with pier and cradle sloped on the southern part of the upper surface to mimic the equator (and so create an equatorial mounting. The plane of the top of the pier passes through the celestial pole.

This is a German style equatorial mounting. An equatorial mounting refers to a type of frame that allows the telescope to move with the rotation of the Earth - one axis is pointed towards the celestial pole (roughly speaking towards the Pole star for the northern hemisphere), the other can then be turned so that the telescope is able to follow a star as the Earth moves. Equatorial mountings come in two main types, English and German. The English style mounting is the shape of a + sign; the German style mounting is more of a T shape.