A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Frank Reed
Date: 2016 Aug 10, 10:29 -0700
A quick note on one detail: the Cyrillic letters which look rather like NAC are actually ИАС, which transliterate to English as "IAS". For a guess, those letters might stand for International Aviation Sextant (these Engish words have cognates in Russian beginning with the same letters).
If your goal is to sell it, ebay is probably the way to go. I would describe it as a "Soviet / Russian aeronautical bubble sextant" vintage c.1960 (a very rough guess). There's really no telling what it's "worth". On items like these, the price you get at auction is really whatever the market will bear. If there's a collector out there eager to get one of these, then the price will be high, perhaps as much as $1000 (again, a very rough guess). On the other hand, if it's too obscure, and there's no one after this particular instrument, then it might go as low as $100. There's only one way to find out!
Conanicut Island USA