1790-1820 Engraved Brass Astrolabe

Description

Beautifully made brass astrolabe-type device. The glass lens makes me think it was for calculating distances, etc. on a map. Engraved markings with early style numerals. A curious piece. Any additional information is welcomed. Unknown maker. Not signed.
Size: 6" diameter.
Condition:Overall excellent. Expected aging and wear. As-Is. Please use photos and description to determine condition.
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