Transit Instrument, by Jesse Ramsden, London, Late 18th Century

Transit telescope, object glass with pivoted cover, screw-fit diagonal eyepiece, opposed-cone axis, one side having an index arm with vernier scale. Near the eyepiece the telescope body is pierced diagonally by an interrupted tapering tube with lenses, possibly for illuminating the cross-wires. Openwork semicircle with four fixing holes and scale [57] to 0 (off centre) to [140], divided to 10, subdivided to 5, to 1 and to 20 minutes, numbered by 10 degrees. Hanging level has adjustable longitudinal level with two sliding markers and short transverse leval. Detached small counterweight and bone (?) reflector on brass mount for cross-wire illumination.