A set of miscellaneous drawings relating to RGO Herstmonceux and also the Roque de los Muchachos Observatory, La Palma. They were originally rolled together in three rolls labelled 'MT Miscellaneous RGO Tracings (not microfilmed)'. The drawings have been arranged in sets according to drawing number where possible; drawing number usually corresponds to size ('V' being the largest and 'Z' the smallest). There are distinct V, W, X, Y and Z sized drawings, and four additional sets, including a set with drawing numbers beginning with 'A1-A4', and sets of RGO administrative templates and organisational charts.

The series includes many drawings of instruments at the Roque de los Muchachos Observatory, La Palma (the William Herschel Telescope and Isaac Newton Telescope), along with works programme charts for the development of the observatory. There are also drawings of buildings and instruments at RGO Herstmonceux and of the AAT [Anglo Australian Telescope].