A large collection of technical drawings, most of which were produced internally by the RGO's Drawing Office, and later, Drawing and Design Offices, based at RGO Herstmonceux. The drawings were originally rolled in brown paper, in sets labelled with alphabetical initials and a title. The original initials, FE, FI, FO, etc. have been retained as part of the reference code for each set.

The sets typically include drawings of five different sizes, marked V, W, X, Y, and Z, V being the largest and Z the smallest. These size signifiers have also been retained as part of the reference code for each group.

The series is arranged in 27 sub-series as follows:

RGO 101/1/FE, FI and FO: drawings of instruments mounted on the Isaac Newton Telescope (INT) at La Palma. FE = the TAURUS-1 Fabry Perot spectrograph and imager; FI = Prime Focus; FO = Coude Spectrograph.

RGO 101/1/MJ: RGO Galaxy plate measuring machine drawings.

RGO 101/1/MK: Miscellaneous RGO General.

RGO 101/1/MM: Solar Dome drawings.

RGO 101/1/MT: Miscellaneous Tracings (including drawings of instruments and buildings from RGO Herstmonceux, the Roque de los Muchachos Observatory, La Palma, and the Anglo Australian Telescope [AAT], along with RGO organisational charts and project planning charts for La Palma).

RGO 101/1/QF: Equatorial Group, Dome B, 36" Refractor (Yapp), and Dome C, 34" Schmitt Camera Building and Dome.

RGO 101/1/QG: Equatorial Group, Dome C, Fridge and Air Drying Plant for Schmitt Camera.

RGO 101/1/QP: Equatorial Group, Dome F, Visual Refractor, main structure.

RGO 101/1/RC: Low Dispersion Survey Spectrograph, A.A.O. (Anglo-Australian Observatory) version.

RGO 101/1/RD1: Instrus. [Instruments] Dev. [Development] and Gen. [General] User. Includes drawings relating to instrumentation for the INT.

RGO 101/1/RD2: Image Photon Counting System (I.P.C.S) camera unit, Unit Spectrograph, Isaac Newton Telescope at La Palma.

RGO 101/1/RI: Image Tube drawings.

RGO 101/1/RY1: Old INT [Isaac Newton Telescope, Herstmonceux], Cassegrain Spectrograph drawings.

RGO 101/1/RY2: Old INT [Isaac Newton Telescope, Herstmonceux], Coudé Spectrograph drawings.

RGO 101/1/RY3: Old INT [Isaac Newton Telescope, Herstmonceux], Unit Spectrograph drawings.

RGO 101/1/RY4: Old INT [Isaac Newton Telescope, Herstmonceux], Miscellaneous drawings.

RGO 101/1/SK: 'RGO Sketches' (miscellaneous, including drawings of instruments and buildings for the Anglo Australian Telescope, Isaac Newton Telescope, Cook Reversible Transit Circle (R.T.C.), Yapp Spectrograph, 150" Stellar Telescope at Kitt Peak, Unit Spectrograph Pretoria, and drawings of the proposed tercentenary sundial at RGO Herstmonceux).

RGO 101/1/TA: Photographic Zenith Tube drawings.

RGO 101/1/TB: Reversible Transit Circle drawings.

RGO 101/1/TC: Mirror Transit Circle drawings.

RGO 101/1/TD: Modified Astrolabe Prism Mount drawings.

RGO 101/1/XA: A.A.T. (Anglo Australian Telescope) drawings.

RGO 101/1/XB: Steavenson Telescope drawings.

RGO 101/1/XC: SAAO (South African Astronomical Observatory) Radcliffe, Pretoria drawings.

RGO 101/1/XD: Sierra Nevada People's Photometer drawings.

Note: foliation [classmark] in bottom right hand corner is by the archivist.