Astro Compass
An Astro Compass is an instrument that first appeared about 1941. It is used to obtain bearings from the sun and / or stars. It is used where magnectic compass's are unreliable, such as near the poles, or in WW2 when they got damaged. There are I understand, certain situtations when GPS are unreliable too, so the astro compass is used as a double check on magnectic compass's and GPS.
Do a Google - Images - Astro Compass - will show several astro compass's.
The one used on the Aries was an unusual special inverted model of the astro compass, presumably because it was mounted near the ceiling of the cockpit, to take readings thro' the upper windscreen.
They are still in use today in Airlines that operate in higher latitudes, I know for certain that Canadian North use then, also Polly Vacher used one too on her solo World flight in a single engined Piper.
I am researching the history and development of the Astro Compass, so would be most grateful for any model numbers, cockpit pictures of installed astro compass's etc., etc.,