Star plotter.

A device to assist rapid plotting of the results of Rapid Sight Reduction without the aid of a parallel rule or dividers. The Astroplot is ingraved on a scale of 5 miles to 1 inch.

Basepate: Constructed of bexoid and containing a rotable disc engraved in degrees from 8-359 around its circumference.
The face of the disc is engraved with 2- miles squares.
Plotting surface: Perspex surface secured above, and proud of, the baseplate.
Time sclae: A bexoid strip, on wich a time scale can be drawn, is provided for insertior between the plotting surface and the baseplate. It is adjustable, pasing throut slots on the East and West sides of the plotting surfaces. Engraved parallel index marks are provided at the slots to ensure that the strip is orientated accurately along the East-West axis.
Altitude ruler: A perspex ruler, engraved in minutes of altitude and fitted with a cursor for setting the controlling altitude for any selected four-minute period.

In fitted wooden case with carrying handle.
20.2" x 16.5" x 2.25" (50.8 x 41.9 x 5.7 cm)