NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Paul Saffo
Date: 2021 Feb 8, 12:16 -0800
Great find, even if the bubble is dry! Robert Eno is the expert on everything Plath, but this was the Plath SOLD AH, variously called "firefly" or "dragonfly" (apparently those terms are incorrect - see below) andbest of the three models of Plath AHs designed over the years, primarily bec it had an adjudtable bubble. The final version, which I had before donating to our Stanford instrument collection was utter trash.
My non-expert opinion is that if one is going to actually use the AH, the best one is the Cassens & Plath AH, which still turn up on eBay from time to time.
Btw, (and not surprisingly) there have been several great discussions about this particular AH on NavList over the years. For ex:
http://fer3.com/arc/m2.aspx/Plath-bubble-sextant-ebay-CP-versus-Plath-Luehmann-mar-2015-g30790
best -p