Groombridge transit circle, consisting of a telescope revolving in the plane of the meridian, two 4-foot declination circles and twelve micrometer microscopes to read off the exact angle at which the telescope is pointing, with accessories and masonry pillar stand, made by Edward Troughton, London, United Kingdom, 1806. Used by Stephen Groombridge to produce the ‘Catalogue of Circumpolar Stars’ in his observatory in Blackheath, London, United Kingdom, 1806-1823, afterwards purchased by Sir James South for his observatory in Campden Hill, Kensington, London, 1823-1870. Originally, the transit circle was fitted with only four micrometer microscopes, but eight additional ones were added by Sir James South. Part of transit circle by Edward Troughton 1806