Prototype beam splitter for the Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO) Astronomy 2008 (prototype)
Filar micrometer, part of refracting telescope by John Smeaton on equatorial mounting with stand [RAS No.7] . Presented to Royal Astronomical Society in 1845 by Mrs Sommerville to whom it was left by Mrs Dixon, Smeaton's daughter. Filar micrometer, from John Smeaton's refracting telescope Astronomy 1770
Two-day chronometer by John Arnold and Son, no.43/133. With inscription "Thos Prest August 10th 1792", scratched on great wheel, Prest was apprenticed to John Arnold and foreman to his son at Chigwell Chronometer Time Measurement
Divided object-lens micrometer by Peter Dollond for cassegrain reflecting Telescope of 2 1/2-inch aperture Astronomy 1754-1757