4.5 inch altazimuth theodolite, mid 18th century.

4.5 inch altazimuth theodolite, mid 18th century.

Altazimuth theodolite, 1775-1785.

Gregorian reflecting telescope of 2 1/2 inch aperture and 8 inch focal length by Robert Brettell, 19th century.

Making observations at the Royal Observatory, Greenwich, London, 1895.

Computer 5.25 ins floppy disk, mid 1980s.

Computer 5.25ins floppy disk, mid 1980s.

Newtonian reflecting telescope, 1783-85.

Interior of a computer floppy disk unit, c 1980s.

Three and a half inch travellers transit theodolite, c 1840.

Three and a half inch travellers transit theodolite, c 1840.

Three and a half inch travellers transit theodolite, c 1840.