Thom, your theory is correct, but I doubt you'd get that accuracy for latitude
unless you spent a lot of time calibrating your knuckles. And determining the
time of local noon is virtually impossible because the Sun "hangs" at noon for a
minute or so. Even with a sextant you wouldn't come within 30 miles of your
position. You might be able to make a better guess with sights an hour before
and after noon, but not with your knuckles.

And one fundamental mistake, Jax didn't talk about a paper astrolabe, he lifted
that directly from the "Latitude 38" web site. Jax can't find his position to
15 miles with a GPS.

BTW, I have a "paper sextant" and a tiny booklet with tables that would allow
pretty accurate navigate, at least compared to "knuckle sights." Its called
"Particularized Navigation" by Frances Wright.

--
-jeff
"Constant Vigilance!" - Frances W. Wright



"Thom Stewart" wrote in message
...
Jax,

I one of your replies, when you were incorrect but close enough, you
made a big thing of concepts. How about in Navi.?

You talk of cardboard "Astrolobes" and being within 60 miles. I can be
within 15 miles just using my fist and watch set to GMT. The Concept
isn't hard; Think about it.

The year is composed of 4 seasons. 365/4 plus 6 hours a year until Leap
Year. That is the time it takes the Earth to go around the Sun. Each
season in determined by the slant of the Earth as compared to the Sun (
If you look on any large scale chart, you will find two lines above and
below the Equator The Tropic of Cancer and the Tropic of Capricorn) They
are found at 221/2 North and 221/2 degrees South. That is the Slant of
the Earth:

Each Season is 91 1/4 divided by 22 1/2=4.05 days per degree. The
average days for a one deg change of sun angle. Since the change is in
the form of a sine wave, we can brake that average down an awful lot by
using RMS average for the observed change at the top of the sine wave.
Roughly the top 29% and 70.7% for the bottom. That my Mensa friend is
basically the Sun Sight Tables

How do you make the angle on the sun;

You make a Fist with your thumb stuck under your fingers to the first
knuckle and extend it at arms length. The fist will be 10 degrees. Each
knuckle to knuckle is 2 degrees, The top of the knuckle to the valley
between the knuckles is 1 degree, half way up the knuckle is a 1/2
degree, the distance in between is 1/4 degree
Now if you use your cap you can shade out the sun until you can detect
just the bottom of the sun. This distance can be measured with fists and
knuckles to the Horizon. ( don't forget to allow for your own height
above) That is your Observed LATITUDE

Longitude; The Earth rotates 360 degrees every 24 hours: 360/24=15
degrees every hour. Zero starts a GMT, Midnigth at International Date
line (180 degrees) Local Noon is when the Sun observed at its highest
(Fist and knuckles)

A CONCEPT that will let you know pretty damn close any where you are in
the world