Logbook so titled, listing photographic plates from the 26" Refractor. A loose note records that the register was made by E.D. Clements (Astrometry) for the creation of permanent card catalogue which could be searchable by field (rather than by plate number). It was approved by the NAO Computer Section in March 1966. Inventory notes dated 1965-1966 on the registers at RGO 156/1/1-15 tie in with this card catalogue.

The logbook contains two handwritten registers of photographic plates, organised by field, with additional notes on the opening pages about the logging system for catalogue cards. Non-parallax fields are listed first (pages 1-333), followed by parallax fields (pages 401-457). Pagination is original, with no pages numbered 334-400. The registers are on printed 'Forms 282', like those at RGO 156/1/1-15, with some column titles changed by hand. Columns include some or all of the following information: plate number, date, object photographed, H.A,. R.A., Dec., duration, shutter and filter (sometimes replaced by 'grating'), Pole (hours) or Equinox, plate (type), and position. There are additional notes on missing plates and periods of inactivity, e.g. '1935 June 18 to Oct 21, 26" Telescope dismounted for alteration and construction of dew cap', etc.

The volume includes ten pages of loose notes and a punched card inside the front cover.