Card correction tables for local solar time and tables of the sun's azimuth in various latitudes, 1942 (c)

The cards also contain instructions on using the Bagnold Sun-Compass, which was invented by Major Ralph Bagnold, the first commander of the Long Range Desert Group (LRDG) during World War Two (1939-1945).

His compass could be used while still driving, unlike other sun compasses that had to be reset in line with the sun whenever vehicles changed course. With the compass fixed to their dashboards, LRDG navigators turned its disc to match the approximate azimuth of the sun (taken from tables of different dates and latitudes) at regular times to maintain their bearing.