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The following message, taken from the Hastro-L (history of astronomy)
mailing list, through a roundabout route, may appeal to those Navlist
members who have recently had enough of celestial navigation.

This one  relates mainly to tidal matters in navigation (so is indirectly,
celestial also). It appeareed a week or so ago

You need to look at the press release and blog, referred to near the end, to
make much sense of it, but that may be worth doing, if you are interested in
such things.

From the information available to me to date, I am not very impressed by the
researchers'  methodology, but that may be unfair, because I haven't read
the actual article in the August Sky & Telescope, which is probably
available in the US by now. All I have to go on as yet are those web pages.

Which leads me to a request. If some Navlist member reads Sky & Telescope,
and has access to that August issue, I wonder if he would kindly take a look
at it, and let me know the actual dates and times of those August 2007
observations that were made at Deal and at Dover. I'm not asking for a scan
of the pages (though wouldn't mind getting one....).

Here follows the forwarded message. Sorry it's going to be a bit chopped-up.

George.

contact George Huxtable at george@huxtable.u-net.com
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.

===========================================

THE FOLLOWING RELEASE WAS RECEIVED FROM SKY & TELESCOPE MAGAZINE, IN
CAMBRIDGE, MASSACHUSETTS, AND IS FORWARDED FOR YOUR INFORMATION.
(FORWARDING DOES NOT IMPLY ENDORSEMENT BY THE AMERICAN ASTRONOMICAL
SOCIETY.)  Steve Maran, American Astronomical Society
steve.maran@aas.org  1-202-328-2010 x116

Astronomers Re-Date Caesar's Invasion of Britain

June 30, 2008

Contacts:
Donald W. Olson, Department of Physics, Texas State University
     1-512-245-2131 , dolson@txstate.edu
Roger W. Sinnott, Senior Editor, Sky & Telescope
    1-617-864-7360 x2146, rsinnott@skyandtelescope.com

Researchers from Texas State University have revised the date when
Julius Caesar
invaded Britain in 55 BC, a transformational event in world history. Despite
what most history books state, Caesar could not have landed on August 26-27.
"The English Channel was flowing the wrong way," says team leader Donald W.
Olson, a tide expert. He and fellow professor Russell Doescher, aided by
astronomy honors students Kellie Beicker and Amanda Gregory, reached this
conclusion during an expedition to England's southern coast last summer.
Earlier, Olson had identified August 2007 as rare opportunity to settle the
longstanding dispute among history scholars and scientists concerning
Caesar's
landing. During that month, complex tidal factors involving the Moon and Sun
would unfold in a near-perfect replay of those in August of 55 BC.
"We realized we could go out in a boat and observe the current for
ourselves,"
Olson explains. "The year 1901 would have been just as good for this
experiment, but no one noticed."

According to Olson's team, Caesar's invasion fleet must have arrived four
days
earlier - August 22-23 in 55 BC - to have acquired a suitable northeastward
current. The revised date reconciles an ancient record of a "falling
tide" with
Caesar's own description of the coastline topography as he moved his
fleet along
the white cliffs of Dover. The Texas researchers present their findings in
the August 2008 Sky & Telescope magazine.

Invasion Fleet Crosses the Channel
When his 100 warships carrying two Roman legions (perhaps 10,000 men)
approached
the white cliffs, Caesar noticed a multitude of javelin-wielding
Celtic warriors
lined up along the ridge and decided to look for a better landing spot. He
ordered his fleet to move along the coast, and after about seven
miles they came to "an open and flat shore."

But which way did Caesar turn - left or right - and when did he actually set
foot on British soil? For centuries, these two questions have vexed not only
historians, but the residents of coastal towns vying for the claim of
"Caesar was here."

Caesar mentioned unexpectedly strong tides, a full Moon, and an ocean
current
that changed direction in mid-afternoon. These clues even led famous
astronomers
Edmond Halley and George Airy to weigh in - but they disagreed with
each other's
conclusions. The debate about the date and place of Caesar's landing has
raged ever since.

The Texas team's revised date, August 22-23, gives Caesar the ocean current
he
needed to maneuver right, proceed seven miles, and land with a
falling tide near
present-day Deal. That's the beach preferred by most historians but
rejected by
tide experts in the past. What's more, a modified reading of Caesar's
reference
to the "night of a full Moon" also leads to the August 22-23 date.

"The scientists were right about the tidal streams," Olson says, "and so
were
the historians about the landing site. With our new result and our new date,
everything is reconciled."

"I had a blast watching these guys in action," says Sky & Telescope Senior
Editor Roger Sinnott, who joined the Texas State expedition last summer.
"One
day they were using GPS to measure their small boat's drift off Dover
harbor,
and on another they were tossing apples from the end of the long Deal pier
to
see which way the current went." Sinnott has been Olson's editor on two
dozen
past projects for Sky & Telescope since 1987.

The Texas researchers have also studied paintings of night scenes by Van
Gogh
and Munch, dated photographs of the Moon by Ansel Adams, and
interpreted cryptic
lines in a Shakespearean play. Closely related to their work on
Caesar is their
earlier research on how the Moon and tides affected the World War II
amphibious
landings on the Pacific atoll of Tarawa and in Normandy on D-day.

Caesar's historic landing in 55 BC was the Roman Empire's first
excursion north
of France, literally to the fringe of the then-known world. When he
crossed the
English Channel again the following summer with a 10-times-larger
fleet, it was
very much like a D-day in reverse.

In their Sky & Telescope article, the Texas State researchers think they've
resolved an age-old debate: When and where did Caesar first land in Britain?

Note to Editors/Producers: Images and a parallel release from Texas State
University are at
http://www.txstate.edu/news/news_releases/news_archive/2008/06/Caesar062308.html
  or you may contact press officer Jayme Blaschke at jb71@txstate.edu

Roger Sinnott's blog relating to this story appears at
http://www.skyandtelescope.com/news/home/21410774.html


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