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» Online Classroom   » Emergency Navigation   » Public Discussion of Emergency Navigation   » Observations underway

Author Topic: Observations underway
Michael Orton

 - posted March 27, 2005 01:13 PM      Profile for Michael Orton           Edit/Delete Post 
I've observed two or three occurences which seem to hold true and
wanted to relate them for your comments.

Voyage from Texas across Atlantic, Mediterranean, Suez, Red Sea up to
Persian Gulf then back out and down to Diego Garcia at 7S, back up to
Kuwait then out and down around Africa staying within the Madagascar
channel, around Agulhas and up to the Caribbean on an straight line.
We're on that part now. From Dec 2004 to present day and it's an area
of 30N to 35S and 77E approx 100W.

1. While Scorpio's tail indicated exact South twice a night it points
southward at all times enough to serve as a generally locater of that

2. When Scorpio is high overhead if you imagine it as in the bottom
of a bowl and draw an imaginary curving line to the rim of the bowl
where it intersects at a right angle that will give you South.

3. The imaginary dot in the south sky indicated by the Southern Cross
or by any of the other techniques is, like Polaris, an indicator of
latitude with no subtraction required.

4. If the imaginary dot of Southern Cross is below the horizon when
looking south or the imaginary dot of Polaris is below the horizon
when looking north, each from the opposite sides of the equator and
you measure the angle from that imaginary interpolated dot to the
equator and subtract it from 90 you have your latitude for that side.

Hope I explained that correctly. If Polaris interpolates as 10 deg.
below the horizon you are 10S....

seems to work so far but I may be missing something.

Michael Orton

 - posted March 27, 2005 01:14 PM      Profile for Michael Orton           Edit/Delete Post 
One observation I forgot to include. We crossed the Tropic of
Capricorn on March 21st around 0400, yesterday in our time zone which
is now Greenwich minus one. Using our bridge wing repeater compass
(gyro system) and an azimuth circle on top I made sunrise at 090 and
sunset at 270. There is a slight error in the sighting ring. Course
204 deg.

At noon I expected the Sun to be over the equator with declination of
zero and we were at 21S, sure enough the angle was the difference of
90 minus 21 or 69 degrees.

The interesting part was the sun rising and setting at due east and
west at the time we had crossed the Tropic or were in it's vicinity
indicating it had curved north that much from sunrise or approximately
the whole 23.27 degrees.

All times are Pacific  
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