Join Date: Apr 2006
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FORGET THE ROSS THEY ARE FOR THE SUCKER TRADE. Literally, they are meant to be sliced up and used as end table lamps or award placques.
The Plath might be real, might be a Cassens & Plath or a "C. Plath", two different firms. Your best bet is to look at the models online and see what you are looking at. There's only one Plath left in business today, and they are very, very, kind to their customers including folks who are trying to buy and repair used instruments. Odds are that you could call them (they respond to emails in English with no problem) with the serial number and description, or email a photo to them, and they would tell you right away what you are looking at.
If a sextant has broken parts, i.e. a cracked mirror or gear, that can often be replaced. (Robt. White out of Boston are one leading source for that, also outstanding folks.) But if the frame itself has been BENT from being dropped, etc., then it may be junk. So you need to take a good look at it, eyeball it closely, and see if there are any signs of gross abuse.
In terms of adjusting...probably Bruce Bauer's "Sextant Book" (I've probably mangled part of that) is the best guide to that. Celestaire.com should have that available on their website, as well as the current Plath sextants.
A Plath was shipped with a certificate of accuracy, but a careful owner can always re-adjust it to original accuracy--if it hasn't been bent. The accuracy from the factory is usually way beyond what even the most proficient small craft navigator can use, so having the actual certificate and knowing the actual limits is of limited value.
When I acquired my Plath I emailed the factory to ask about a manual, spare bulbs, and whether a new part could be obtained (one of the plastic parts had cracked, unseen until I stripped it down). I didn't hear from them, so I made up a new part from some brass stock. A week later...there was an air mail packet in my mail box. Two new bulbs, new manual, new plastic bit, letter thanking me for becoming an owner, AND a little brass plaque with my name engraved on it.
Customer service doesn't get any better than that!
Any full-sized Plath, even needing some TLC, for $225 US would be a steal. the top models sell for about $550-600 on eBay when and if they come around, there's not much traffic in the sextant market these days.