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Subject: Re: Sextant Accuracy and anomalous dip
From: Bruce Stark (Stark4677@XXX.XXX)
Date: Fri Mar 21 2003 - 18:53:37 EST
Thanks to Fred, Jared, and Lee, I've had the pleasure of reading Capt.
Combe's account of his experiences on a cable repair ship. Since most of my
working life was spent first as a logger, and then as a millwright in a pulp
and paper mill, I may get more out of some parts than others do. Thank God we
never had to contend with all that raging salt water!
Fred is right. They weren't taking equal altitudes. They were taking time
sights. LOTS of time sights. For the first hundred years or so these were
known as "Observations for the TIme," and that's what Capt. Combe calls them.
I expect he already had the longitude. It's only reasonable to suppose that,
as soon as a cable was laid, Greenwich time was telegraphed from an
observatory so observers at the new station could determine the station's
exact position. By finding the local time at the station, and applying the
station's longitude to it, Combe found the time at Greenwich, and thus the
error of the ship's chronometers on Greenwich.
Combe says "9 kph" be cause it was the norm, then, to call knots "knots per
hour."
Bruce
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