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Gary adds:

Go to the on line publications link then scroll down and you can also
download Ho229 and HO 249.
 Here is a link to a site where you can download for free varius
 navigational publications including the American Practical Navigator,
HO
 9, Bowditch. Table 14 is the dip short of the horizon table.http://
164.214.12.145/index/index.html
gl

On Nov 27, 11:33 pm, "Gary J. LaPook"  wrote:
> Gary LaPook wrote:
>
> Here is a link to a site where you can download for free varius
> navigational publications including the American Practical Navigator, HO
> 9, Bowditch. Table 14 is the dip short of the horizon table.http://164.214.12.145/index/index.html
> gl
>
> Rebecca Lowry wrote:
> > Hi,
>
> > I'm also in the process of learning.
>
> > Any chance you could send, or email, a couple to me as well?
>
> > thanks,
> > Wayne Lowry
> > 93915 prairie rd
> > Junction city, Oregon 97448
> > USA
>
> > Greg Rudzinski  wrote:
>
> >     I suggest demonstrating a polaris observation to your young students
> >     using the far shore of a lake as a horizon. Bowditch table 22 will
> >     give you the dip correction. A pub. 249 vol. 1. table 6. correction
> >     needs to be made (up to 44 minutes of arc). Table 6. requires a local
> >     hour angle of Aries entry. I have a homemade pocket table that
> >     simplifies some of this. E-mail me a mailing address and I will send
> >     you a few.
>
> >     Greg Rudzinski
> >     gregrudzin...@yahoo.com
>
> >     On Nov 27, 7:20 am, Isonomia wrote:
> >     > I'm camping next summer with a load of 11year old kids and wanted to
> >     > do some celestrial navigation and plot a position to within
> >     > 10-20miles.
>
> >     > Has anyone ever built a simple theodolite type sextant out of basic
> >     > DIY material and managed to obtain an accuracy that would allow a
> >     > basic position plot and if so how?
>
> >     > In particular I would like to build a form of "sextant" based on
> >     > measuring the angle above a horizontal plane of the sun using the
> >     > sun's shadow.
>
> >     > I'd welcome comments, suggestions or practical experience on:-
>
> >     > 1. How to create a horizontal plane to within a few minutes
> >     accuracy?
> >     > 2. How to obtain a good shadow/image, e.g. has anyone tried glass
> >     > lenses?
> >     > 3. How to measure an angle from the horizontal to the sun's
> >     image to a
> >     > few minutes?
>
> >     > All contributions greatfully received.
>
> >     > Mike
>
> >     > HISTORY & WHAT I'VE STOPPED CONSIDERING
>
> >     > I started by considering using a sextant with an artificial horizon.
> >     > However, whereas it is a skill to find the sun and line it up
> >     with the
> >     > horizon (sea=go up, sky=go down), trying to line up two images
> >     of the
> >     > sun is an art. And aligning two images of stars is so difficult I've
> >     > only managed a sensible result on 50% of my tries.
>
> >     > My next idea was to use a real artificial horizon, in the shape of a
> >     > string set at a distance to give a low arc error. However, after
> >     a bit
> >     > of calculation regarding the distance (30-100m) and the length
> >     of the
> >     > string (10-30m), I've realised that any string big enough to see is
> >     > going to dip considerably unless it is under such extreme
> >     tension that
> >     > it is a positive hazard in an open area.
>
> >     > I then considered laser levels - but I'm not looking through a
> >     sextant
> >     > with potential laser reflections all over place - even if one could
> >     > see the laser line in daylight at the distance required.
> >     ------------------------------------------------------------------------
> >     Be a better sports nut! Let your teams follow you with Yahoo
> >     Mobile. Try it now.
> >     
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