NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Watch into Compass?
From: Frank Reed CT
Date: 2004 Feb 12, 17:06 EST
From: Frank Reed CT
Date: 2004 Feb 12, 17:06 EST
Joel J wrote:
"The way I recall the Boy Scout method was to use a tall stick, and scribe a
circle in the dirt around it. Boy Scouts carried a compass and that was how
N and 1 was oriented. Then it was just a matter of dividing the circle into
12 ths or more.
The shadow pointed at the time. "
That's a different trick. It also runs into problems for the very same reason: it confuses local hour angle with azimuth. The greatest advance in the history of sundial design was the realization that the whole thing has to be tilted. A sundial drawn flat on the ground works poorly.
Here is one of many web sites that includes the watch trick that we were talking about. It also includes another method using the Sun to determine compass directions (does that one work?):
http://smct.armystudyguide.com/Skill_Level_1-AUG2003/lnt14.htm
At least they remembered to include the Big Dipper and the North Star! Incidentally, the star Mintaka (in Orion's belt) always rises very close to due east and sets very close to due west everywhere in the world. The declination of the star is near zero. This was a popular trick often mentioned by the lecturers at the Mystic Seaport Planetarium.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
"The way I recall the Boy Scout method was to use a tall stick, and scribe a
circle in the dirt around it. Boy Scouts carried a compass and that was how
N and 1 was oriented. Then it was just a matter of dividing the circle into
12 ths or more.
The shadow pointed at the time. "
That's a different trick. It also runs into problems for the very same reason: it confuses local hour angle with azimuth. The greatest advance in the history of sundial design was the realization that the whole thing has to be tilted. A sundial drawn flat on the ground works poorly.
Here is one of many web sites that includes the watch trick that we were talking about. It also includes another method using the Sun to determine compass directions (does that one work?):
http://smct.armystudyguide.com/Skill_Level_1-AUG2003/lnt14.htm
At least they remembered to include the Big Dipper and the North Star! Incidentally, the star Mintaka (in Orion's belt) always rises very close to due east and sets very close to due west everywhere in the world. The declination of the star is near zero. This was a popular trick often mentioned by the lecturers at the Mystic Seaport Planetarium.
Frank E. Reed
[X] Mystic, Connecticut
[ ] Chicago, Illinois
