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Allow me to echo everyone's comments about the Davis and Celesticomp.

One of the absolute thrills as a celestial student is taking your first
shots (from an known point, probably on land), reducing them, and plotting
a LOP which BY GOD IS CLOSE TO WHERE I TOOK THE SHOT!!!!   Makes one feel
like Christopher Columbus (ignoring all the side discussions of whether he
used celestial at all :-).

One can probably learn celestial using the $20 Davis Mark 3 sextant (and
people have even used it for offshore navigation) but the thrill of seeing
a LOP within a mile or two of your position likely will not occur -- the
instrument is just not that accurate.

The more expensive Davis's are good learning instruments.  I've seen lots
of students in the Power Squadron courses (including myself) achieve fine
results with them.  You don't have to get a Mark 25 -- IMHO (which others
on the list may disagree with), half-silvered mirrors are just as good as
full-silvered but transparent mirrors.  The Davis Mk 15 and Mk 20 are
exactly the same sextants except with the half-silvered mirrors.  The Mk 15
does not have a nighttime illuminator, but one might do just as well with a
penlight (especially one of the $9.95 laser pointers which are so popular
(and controversial) among schoolchildren).  Glancing at the latest West
catalog, a Mk 15 is $109 as opposed to $189 for a Mk 25.

I also think that with a simple scientific calculator (about $15 at KMart)
you can do perfectly fine sight reductions using an almanac for the body's
position and then standard spherical trig for intercept and azimuth.  And
you'll learn a lot more about the steps involved in sight reduction.

To stir some additional controversy:  I just don't get the people who say
"use celestial, don't depend on electronics because you never know when
they will fail" and then happily use a Celesticomp.

Lu Abel

At 01:30 PM 7/27/99 GMT, you wrote:
>        Im a beginning Celestial Navigator and am seeking some
>advise...I have access to a Davis MK25 Sextant to learn with..or
>SHould I purchase the Astra IIIb to learn with..?? I don't plan any
>crossing in the immediate future...One other thing, I was also
>thinking of purchasing the Celesticomp V for checking my math and
>learning with it. or should I pass on the puter to learn the
>conventional way....
>
>                                Thanks
>
>                                        Barry
>
>P.S. If this has been discussed before I apologize, I cant find an
>archive..!!
>

   

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