Aircraft Bubble Sextant, USSR, NAC-1 1948 (SEXT18)
This is an early Cold-War-era aeronautical sextant from the former Soviet Union. Includes case and manual, not shown.
According to collector George Fulford's notes:
The date suggests this most probably came from the first batch of Soviet copies of the German WW2 Plath Kriegsmarine bubble sextant. They name it the NAC-1 and you can appreciate how rough it was post war over there by the two manuals that came with it. The ‘how to’ one has the diagrams and photos of the instrument individually glued on to the pages. The registration booklet looks like a passport. There are nine different official stamps from various authorities scattered throughout the 21 pages. The first was in 1948 and last in 1988.