At anchor Baie de Taiohae, Nuku Hiva
Wind: Light, variable
Weather: Mostly sunny, warm.
**
Not a lot happening, waiting for the crown for my broken tooth to be made,
should be finished on Thursday. Meanwhile doing some maintenance and reading
up on the archaic art of celestial navigation:
Why 360 degrees in a circle?
If you were an early astronomer you would have noticed that the stars
rotate counterclockwise (ccw) about Polaris at the rate of seemingly once
per
day. And that as the year moved on the constellation's position would
slowly
crank around as well, once per year ccw. The planets were mysterious and
thought to be gods as they roamed around the night sky, only going through
certain constellations named the zodiac (in the ecliptic plane). You would
have
noticed that after ¼ of a year had passed, or ~ 90 days, that the
constellation
had turned ccw about ¼ of a circle. It would have seemed that the angle of
rotation per day was 1/90 of a quarter circle. A degree could be thought of
as
a heavenly angular unit, which is quite a coincidence with the Babylonian
base
60 number system which established the angle of an equilateral triangle as
60º.
The Egyptians had divided the day into 24 hours, and the
Mesopotamians further divided the hour into 60 minutes, 60 seconds per
minute. It is easy to see the analogy between angle and clock time, since
the
angle was further divided into 60 arcminutes per degree, and 60 arcseconds
per
arcminute. An arcminute of a great circle on the surface of our planet
defined
the unit of distance; a nautical mile, which = 1.15 statute miles. By the
way,
mile comes from the Latin milia for 1000 double paces of a Roman soldier.
From "Celestial Navigation in a Teacup" by Rodger E. Farley.
How very interesting, don't you think?
**
All is well.
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