An orrery with interchangeable planetarium and tellurium fittings, sharing a wooden circular baseboard with paper scale, standing on three legs. The orbits of Earth, Mars, Jupiter and Saturn are shown on the baseboard , and also the orbits of three comets. One of these comet orbits is Halley's (marked 1759 and 1835) another is marked 1105 and 1680 (Halley erroneously thought that the comets of these two dates were the same). The other comet (marked 1661 and 1789) would appear to be the one for which Halley made calculations 1680s, suggesting that it was a return of the comet of 1532. Further calculations were made by Nevil Maskelyne, who predicted a reappearance of this comet in 1789, but none appeared. This would appear to date this orrery to that year, or shortly before. A date between 1787-1790 is suggested by the appearance of Uranus with two moons (between 1790 and 1846 many instruments showed Uranus with 6 satellites owing to erroneous sightings by William Herschel).

The planetarium attachment (AST1061.1) shows the Sun, Mercury, Venus, Earth and Moon, Mars, Jupiter (with 4 moons) Saturn (with no ring, but 7 moons), Uranus (with 2 moons). An old inventory card states that the Saturn globe has been reconstructed.

The lunarium attachment has geared wheels to show the movement of the Moon around the Earth, and the daily motion of the earth. The models of the Moon and Earth are in ivory, the latter with lines of longitude, equator, tropics and equatroial marked, and the Sun is brass. The moon is jammed, but the gears can still be moved by hand. The attachment is inscribed "W. Harris No 17[?] High Holborn. London". There is a small lamp (AST1061.2) to be used instead of the model of the Sun. The original fitted box (AST1061.3) is also in the collection. The following inscription appears inside the lid: "William Harris/ Mathematical, Optical & philosophical/ INSTRUMENT MAKER/ No 47 High Holborn, nearly opposite Chancery Lane, London/ Austin Sculp.s Clerken[we]ll".

William Harris is known to have been apprenticed to Joseph Robison in 1788, which, if the above suggestions of dating are correct, would make this a very early example of his work. It is, of course, possible that Harris was making use of out-dated information or parts. He is known to have been based at 47 High Holborn from at least 1805. (See G. Clifton, Directory of British Scientific Instrument Makers, 1550-1851). Harris was later Master of the Clockmakers Company, 1830-32.