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Re: Can someone identify this
From: George Huxtable
Date: 2008 Nov 11, 22:56 -0000
From: George Huxtable
Date: 2008 Nov 11, 22:56 -0000
D Walsen and I both found our way to the same US patent, and both posted it as an attachment, so I will not do so again. But somehow, my text got hopelessly garbled. I'm not sure how it happened, but here's the text part again, with my apologies. ========================= Bruce Hamilton asked- "Can someone identify this Anyone need something for their collection? What exactly is it? http://cgi.ebay.ca/ASTRONOMIC-CALCULATOR-SEXTANT-theodolite_W0QQitemZ190265697439QQcmdZViewItem?hash=item190265697439&_trksid=p3286.c0.m14&_trkparms=72%3A1215%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318 " ===================== It's a Zerbee "Fix Finder".Perhaps it's THE Zerbee Fix Finder. described in the US patent 2519532 , attached. It could be the prototype, perhaps the one-and-only, because it's labelled serial number 1; the invention of LouisB Zerbee, patent granted 1950. You can dial up the details in GooglePatents. I've never seen one or even heard of it before. It claims to be able tosolve one OR MORE spherical triangles, simultaneously, so could presumably result in a fix from a pair of star altitudes. I admit to not having studied the details of the patent in any detail. These things are written in a special arcane language that seems intended to obscure more than it reveals. It seems to be a development of the armillary sphere, an analogue representation of the Earth and sky, allowing spherical triangles to be solved. Such armillary spheres first appeared in China in the first-century BC. The nearest thing to this device I've seen (in print) is the Mariner's Calculator, in Janet Taylor's "Navigation simplified" of 1849, but that could solve only one spherical triangle at a time. But this one is FAR more sophisticated. Just look at the profusion of arcscales, each fitted with its own micrometer readout. No expense has been spared in its construction; which may be why it wasn't developed further. It would be interesting to discover what accuracy was achievable. It's the sort of instrument I would love to own. You could play with it for hours. I expect it will fetch a lot more than the present bid, and should really find a home in a museum. Perhaps a Museum of Complication, if such a speciality exists. contact George Huxtable, now at george@hux.me.uk or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.Navigation List archive: www.fer3.com/arc --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To unsubscribe, email NavList-unsubscribe@fer3.com -~----------~----~----~----~------~----~------~--~---