NavList:

   

Reply

In answer to your question about bubble attachments, I believe a C.Plath
attachment will fit your Japanese sextant (Tamaya?).

My own personal opinion -- based on experience -- is that whatever bubble
attachment you can lay your hands on, it should have a provision for
adjusting the size of the bubble. As I alluded to before, C.Plath made the
best marine sextant bubble attachments, bar none. There are still quite a
few kicking around out there but they are becoming harder and harder to
find. I recall Ken Gebhart from Celestaire came into a considerable number
of them a few years back and I think they sold out fairly quickly.

In terms of accuracy, at sea, a bubble attachment is near useless unless the
water is as flat as piss on a plate. The general movement of a vessel at
sea -- even a gentle movement -- is such that the bubble scoots all over the
field of view like a blue-arsed fly at a road kill. The best I have ever
managed (at sea) on a calm day was about 3 - 5 miles.

On land, and with a lot of practice, you can nail your position down to
within tenths of a nautical mile, but normally you will be in the range of
1 - 3 nautical miles.

The RAE MK IXA Aircraft bubble sextant is even more accurate on land and
much easier to use. It has probably the best bubble system ever devised.

Your comment on limiting factors in sextant accuracy made me smile. My
sextant has the same problem!

Robert

----- Original Message -----
From: "cfi@licfi.com" 
To: 
Sent: Thursday, June 01, 2006 1:43 PM
Subject: Re: The Perfect Sextant


>I have a all metal Japanese sextant from e-bay that the owner said got him
> across the pacific several times(made by a: "Measure All Company" ?), its
> no C.Plath but it reads out to 10" of arc and as far as I can tell I am
> the
> limiting factor when it comes to sights. I would really like to find a
> bubble attachment for it; (1)does anyone have any suggestions? & (2)what
> is
> the best accuracy you can expect with a bubble, is it worth the bother?
>
> Original Message:

   

Reply