Cataloguing and conservation of this class is still in progress. For all queries and requests for access, please contact the RGO Archivist, Dr Emma Saunders, at els57@cam.ac.uk.

A large collection of technical drawings and plans of telescopes, instruments and buildings of the Royal Observatory Greenwich and RGO Herstmonceux.

The largest series (RGO 101/1) comprises drawings made internally by the RGO's Drawing Office, and later, 'Drawing and Design Offices', based at RGO Herstmonceux (Herstmonceux Castle, Sussex).

The Royal Observatory Greenwich series (RGO 101/2) includes 18th century drawings and watercolours of the Observatory, mid-late 19th century plans of Greenwich Park, and drawings of instruments and buildings, such as Airy's Transit Circle, the Astrographic Dome, the New Physical Observatory, the Lassell 30ft Dome and New Equatorial. Most date to the time of George Airy and many are drawn or annotated by him.

The RGO Herstmonceux series (RGO 101/3) includes plans of Herstmonceux Castle, Sussex, and of newly built RGO structures there, including the Equatorial Group of Telescopes, Meridian Group of Telescopes, West Building (housing the Time and Nautical Almanac Building, Chronometer Workshop, Electronics and Engineering Workshops etc.), and Isaac Newton Telescope Dome. Notable are the colour drawings of the staircase of Herstmonceux Castle (RGO 101/3/2/1) and of the Equatorial Group of Telescopes by Brian O'Rorke (RGO 101/3/5/1/18-22). The series also includes technical drawings of telescopes and instruments, including drawings of the Photographic Zenith Tube and Yapp 36'' Reflector. Many of the plans and drawings in this series were created by external agencies, including architect Brian O'Rorke and Grubb Parsons and Co.

The collection also includes various sets of Ordnance Survey maps of Herstmonceux and the surroundings areas (RGO 101/4) including a large set of early 19th century 1 inch maps of the South of England, originally bound together.

The final series is comprised of maritime charts dated c.1801-1874. They include maps of Mackenzies Track in America, a chart of the 1822 voyage of the Mary Ann travelling from London to Jamaica, a chart to find longitiude at sea, a map of Accessible Bay at Kerguelen Island, and a Sketch of Sidney Cove (RGO 101/5).