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Are there any sources for these sextants?  HewS

On 7/11/08, engineer  wrote:
>
>  The British Mk IX is about 200 grams lighter. and is  my favourite
>  because all the controls come readily to hand, it is easy to use and
>  read and you have a reasonable chance of getting one that works. With
>  the exception of the averager on the Mk IX A, the works of the Mk IX
>  series are accesible and usually easy to fix. The bubble assembly is
>  also easy to refill.
>
>  My A7 has a vapour pressure bubble chamber which, if empty when you
>  get it is very difficult for the non-specialist to refill. Many of the
>  WW II US instruments suffered from "complification" and some used 4
>  prisms, heavy and expensive to produce. The AN 5854-1's
>  averager(strictly, a median device)is temperamental and hard to fix if
>  it has suffered corrosion in storage. The AN 5851(Navy Mk 5)is heavy
>  and clunky and initial setting of its averager needs care. The A10-A
>  is perhaps the handiest instrument to use, provided the electrical
>  marking system is in good order. It is not impossible for
>  a reasonably handy person to fix the system, once it has been
>  understood. The A10 uses the Mark I finger to operate the marking
>  pencil. That leaves rarer instruments, like the A8-A and the Navy Mk
>  IV. The latter was plainly not a success and if you find one, the
>  averaging system will tax the average person to fix. The A12 is a
>  favourite of many people and was designed to be cheap to produce(some
>  of the others cost almost the price of a small home to produce). The
>  arc and vernier on mine are poorly cut, but if you can get one free
>  from corrosion and in working order it would be a good one to start
>  with.
>
>  The Achilles heel of nearly all the bubble sextants is the bubble
>  chamber. For practical purposes, you cannot refill a vapour pressure
>  chamber. Happily, most of the later bubble sextant produced used a
>  different system with an air reservoir; and these are fairly easy to
>  refill. The MA series are, alas, expensive and do not often come on to
>  the market.
>
>  Bill Morris
>
>
>  On Jul 11, 1:54 pm, "Gary J. LaPook"  wrote:
>  > My fravorite is my MA-1 which isn't a bubble sextant but a pendulous
>  > mirror type and my second favorite is the MA-2 with a bubble. If you
>  > want a light, simple sextant get a Bendix A-7, it is the lightest bubble
>  > sextant I have.
>  >
>  > gl
>  >
>  >
>  >
>
> > glap...@pacbell.net wrote:
>  > >Here is a link to a site with discriptions of many types of bubble
>  > >sextants:
>  >
>  > >http://home.earthlink.net/%7Es543t-24dst/airnav/index.html
>  >
>  > >gl
>  >
>  > >On Jul 5, 3:19 am, glap...@pacbell.net wrote:
>  >
>  > >>You should also check the files section of the Yahoo sextant group for
>  > >>more information on sextants.
>  >
>  > >>http://groups.yahoo.com/group/Sextants/files/
>  >
>  > >>gl
>  >
>  > >>On Jul 3, 5:14 pm, bubi352  wrote:
>  >
>  > >>>I am new to this group and new to celestial navigation. I currently
>  > >>>work as an airline pilot and fly extensively over water at night. I
>  > >>>have developed a keen interest in determining my position the old
>  > >>>fashion way.
>  >
>  > >>>Could someone tell me which bubble sextant I should buy?
>  > >>>What should I be looking on a bubble sextant?
>  > >>>Where can I buy one?
>  >
>  > >>>Thank you in advance.
>  >
>
> > >>>Bubi- Hide quoted text -
>  >
>  > - Show quoted text -
>  >
>

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