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Jeff Morris
 
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Default Question: Judging High Tide by the Moon

Ok, I'll give it a try -

Halfway between moonrise and moonset is 10 pm local time, which is the time of
transit of the local meridian. To this we must add the "Local Establishment" or
the "Lunitidal Interval" (actually the proper terms are "high water full and
change" or "mean high water lunitidal interval") to get the time of the next
high tide.

This was published on old charts. My 1867 Boston Harbor chart lists the
"Corrected Establishment" (average of all high water intervals) for Boston Light
as "XIh XIIm". This mean you add 11 hours and 12 minutes to the time of local
meridian passage of the moon to get the time of the next high tide.

Tides watches usually require setting the Lunitidal Interval for a particular
spot. Of course, this only works for semidiurnal tides.


"Bart Senior" wrote in message
. net...
Moonrise 4 pm local time
Moonset 4 am local time

Approximately when is high tide? [ 1 pt ]