It has been nearly a century since a solar eclipse covered America . It
will take four hours and 24 minutes as Earth turns while the moon moves
east 2.36 degrees. That may not sound like much, but it was a critical
difference in the 16th century when Europeans were trying to accurately map and
navigate the world.
The determination of longitude in the 16th century was difficult as the method developed by Phoenician cartographers was secret and vanished into the mists of time. In antiquity
Ancient mariners only wanted to know of ports, the rest of it was scenery and they were not tourists. In boats advancing only 20 miles a day they could die of thirst or starve if they wandered. And, wander they did: Surface winds blow many ways on the high seas. Knowing where they were and going was life or death.
My interest in this began as a boy on a fishing trip to
In Columbus '
time longitude was determined by recording local time of an eclipse, then
compare it to the local time the event was seen at a home base. In antiquity it
was Alexandria , Egypt ,
in Columbus era Salamanca ,
Spain and finally Greenwich , England
to date.
Every hour of difference is 15 degrees east or west of the base, but for a long time they did not realize they were not seeing the same event in time! For every hour of difference there was a 0.536 degree error. It may not sound like much, but from
Christopher Columbus made two location attempts in the
It is believed error correction was first done by cartographers in
One of their maps included our Saint Lawrence River confirming what I saw
In a 1974 book project I saw a way the charts could be done using solar-lunar intervals which occur every month and not rarely like eclipses as that would better explain the Phoenician's abilities. I had a series of visions that were either the way our minds work or were navigations of time. I know not which.
My concept was published in the seventh edition of "The Maps
of the Ancient Sea Kings," by Dr. Charles Hapgood, a leading authority on
cartography, then noticed by Smithsonian Institution Magazine editors who were
preparing an issue on navigation in antiquity. They asked me to make a
contribution and try my method on the work of Captain John Cook who by a secret method placed
islands in the South Pacific so accurately their positions were not improved
until satellites were used geographically. Could I show Cook used a
similar method?
Meanwhile back at the couch and naps I found Cook and saw flashes of setting up pendulum clocks instead of free pendula used by the Phoenicians, but did not see, or imagine, the work. Nonetheless, I felt I knew what they were doing so I did calculations on one island.
The Smithsonian people wanted confirmation so I found other islands Cook had located and their gravity constants. Where pendula were involved any difference would affect the positions. On my submission the Smithsonian contacted the British Admiralty for confirmation, but were told Cook's work was a state secret! 200 years later? I suspect they simply did not want to be bothered or have to admit they had destroyed Cooks work, but the matter was unresolved. Thus what I had done was a "speculation" on publication.
Our August 21, 2017 eclipse may not be of importance, but it was once an event on which important men's lives were in the balance and we note that on the day of the eclipse.
Adrian Vance
Audio Archive: 5 minutes, 30 seconds
https://archive.org/details/DayOfTheEclipse_201708
Broadcasters: PD: Please use freely.

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