A series of registers of photographic plates taken with the 13-inch Astrographic Telescope at the Royal Observatory, Greenwich and Herstmonceux. Many of the plates were taken for the Carte du Ciel project, photography for which was completed in December 1909 (see note in volume RGO 156/2/7).

Apart from the first volume which is handwritten, the volumes are comprised of bound printed 'Form No. 261's, with handwritten entries. Column headings are: no. of photo, date, position of telescope, orient. of screw, observer (initials), R.A., Dec. North, Micrometer scale readings (R.A. and Dec.), clock times of exposures (begin, end, duration), barometer (external and internal therm.), plate and development, remarks (e.g. dark, good, duplicate, etc.), signature. The 'remarks column' often includes comments on visibility, issues with instruments or plates (e.g. accidental breakage) or notes on adjustments. Many plates are also marked 'Chart' or 'Cat' [Catalogue] in red.

Significantly, volumes RGO 156/2/1-3 include entries made by William Christies' "Lady Computers", Alice Everett (A.E.), Edith Rix (E.R./E.M.R.), and Annie Russell (A.R.), all of whom observed and took photographs with the 13-inch Astrographic for the Carte du Ciel. In addition to stars, objects imaged include periodic comets, planets, novae, nebulae, and asteroids, etc. Full names of observers can be identified by checking the introduction to the publication 'Greenwich Observations' for the relevant years.

Related records are at the following classmarks: RGO 163 (including adjustments to the instrument), RGO 70/7 (observer's logbooks). Please note that both RGO 70/7 and the original glass plates made with the Astrographic Telescope are held by the Bodleian Library, not Cambridge University Library.