NavList:

Corallina, you wrote:
"I remember reading  that Harrison used a star and a vertical edge to measure
a sideral day.   This should allow for a somewhat precise measure of time and
the accuracy of  ones timing device, probably good to a few seconds of
accuracy."

Yes,  it's a very accurate test. This was widely understood to be the best
way to test  a clock 300 years ago. Some accounts have "marvelled" at Harrison's
use of stars  for testing his clocks. In the day, among people who bothered
to understand  clocks, I don't think anyone would have been overly impressed.
That's simply how  you did it. Of course they might have been shocked if they
mistakenly took  Harrison for "a mere country  carpenter".

-FER
http://www.HistoricalAtlas.com/lunars 


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