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George,

As Robert Gainer said.  The other thing to do is ask the seller to
email pictures to you.  Most people should have or have a friend with
a digital camera with enough resolution to show all the arc
divisions.  Of course you would need two pictures to avoid the index
arm obscuring.  Not everybody will have the skill to take a usable
picture, but....

Fred


On Apr 27, 2006, at 5:10 PM, George Huxtable wrote:

> On this list, I have frequently expressed my opinion that a cheapo
> plastic sextant is the appropriate instrument to carry on a small
> boat, in view of the rough-and-ready nature of the observations
> that result from an unstable platform underfoot, and a viewpoint so
> close to the waves. That remains my view.
>
> However, in recent years I have coveted a "real" sextant, and
> particularly a Vernier instrument rather than a micrometer. For
> historical reasons, mostly, in that the basic design of a Vernier
> sextant remains unaltered since its introduction about 250 years
> ago. Although I might keep it on the mantlepiece, rather than
> install it on my little boat, it would not be just an ornament, but
> would be asked to do a proper job. Such as measuring lunar
> distances, for example; a precise task which my plastic Ebbco is
> certainly not up to. I am quite aware that the micrometer sextant
> was a real advance, making it much easier to read an angle,
> without sacrificing precision. But the nice thing about the Vernier
> is that its precision is so apparent, demonstrated just by a
> close look at the nicety of the scale divisions, though my old eyes
> are probably not good enought to do it justice. Anyway, A
> Vernier sextant it was to be.
>
> Alex Eremenko has also expressed interest, in a thread "Problem
> with a sextant", when he wrote-
>
>  "And I hope my next sextant will be one of those old ones with
> Vernier and microscope and no teeth to worry about! If I find a good
> one."
>
> I have been keeping my eye on Ebay, the UK version ebay.co.uk, and
> decided to bid for a 1920's Heath Hezzanith Vernier sextant that
> appeared.. That model was the "standard" British instrument of its
> time, widely sold and used. It was being sold by a fellow who had
> used it, as a navigating officer in the 1960's, and had inherited
> it from his father who had possessed it since the start of his
> merchant-navy career, in the 1920's. So: good provenance, no
> antique-dealers involved to add their markup and polish the
> scale-divisions off the arc. It was stated that mirrors, shades,
> and arc were all in perfect condition, though a brass spring-clip
> (that opposed the action of a mirror adjusting screw) was broken
> and needed replacement. That wouldn't present a problem. What more
> could anyone ask? So I bid, and as there was little contest, got it
> as ?185 (about $300 by my reckoning), which pleased me as quite
> a bargain. I would have paid more. It was interesting to get a
> message from another mariner, after the bidding had finished, to say
> that he had been unable to bid, and offering to buy from me for
> more than I had paid.
>
> A point that the seller had emphasised was that although Brasso had
> been used to polish other parts, only breadcrumbs were ever used
> to clean the silver arc  (a trick I had heard of before). I made a
> long drive to collect it, and it was a surprise to discover that
> although all the other claims were indeed true, there were serious
> problems with the arc. Although, over most of the arc, the fine
> divisions were clear and sharp, at angles less than 10 degrees,
> they had become faint and hard to read. Below 5 degrees, through the
> zero-point, to the end of the off-the arc section, there was no
> trace of any fine-divisions whatsoever. They had been completely
> polished off. That, of course, made it quite unusable as a
> measuring instrument, though it would still have some value as an
> ornament.
>
> By this time, money had already changed hands, and the seller
> didn't quibble at all about making a full refund. That put me back
> where I had started off except for my wasted time, and a wasted
> long journey through the West-country. Not entirely wasted, I should
> add; glorious Spring weather, lots of blossom out, England at its
> (rare) best.
>
> My experience shows up the problems that can occur when you buy
> something as finicky as a sextant, sight unseen, at auction. Will I
> be tempted to try again? Probably, yes. What more can I do to avoid
> another disappointment? I have no idea. Perhaps others, with
> more experience of these matters, can offer suggestions.
>
> George.
>
> ===============
>
> contact George Huxtable at george@huxtable.u-net.com
> or at +44 1865 820222 (from UK, 01865 820222)
> or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.

   

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