Astro Tracker Field-of-View Air Navigation Computer CPU-300

This is a USAF celestial navigation computer CPU-300 to assist in the identification of stars in the field-of-view and to plot the aircraft's position. We have been told, but cannot confirm, that this was used in conjunction with the MD-1 Automatic Astro Tracker System used in B-52 Stratofortress strategic bomber.  

The 10 x 10 inch kit comes with 13 clear overlays, 10 of which contain gradients of latitude. The navigator would select the overlay representing the gradients for the night sky for the known rough latitude of the aircraft, and would rotate the overlay and use that information to position the stars and the aircraft accordingly.  

The kit is in good condition given its age.