... Armagh Observatory, College Hill, Armagh BT61 9DG, +44 (0)28 3752 2928 . 6-inch Reflector by Thomas Short, London. 1768/1769. 2/1371 - 24, 2 feet focal length. ... This telescope, with a 6-inch mirror and 2-foot focal length, was used by King George III at Kew Observatory to observe the 1769 transit of Venus. It consists of a brass tube supported on a brass pillar and tripod, with interchangeable eyepieces, surmounted by a smaller finder telescope. ... The accessories include a solar filter. ...