Question: Judging High Tide by the Moon
 

"Jeff Morris" wrote in message
...
"Donal" wrote in message
...
All I need to know is that when there is a full, or new, moon the HW
will be
around 13:00.

Well, there are a few other details that aren't stated, like the
presumption the
tides are semi-diurnal.

If you know the times of moonrise/moonset then the relationship between
lunar
noon (the midpoint of rise and set) and high tide is relatively fixed.
Thus,
the relationship you observe about the time of high tide and the state of
the
moon can be used throughout the month.

I'm assuming you're talking about Portsmouth. If so, you should double
check
your understanding of the tides. Full Moon last occurred on about 5 hours
ago,
May 4 at 9:35 pm BST. High tide was at 12:06 am on May 5.

Fair enough! I should have said that springs were at 13:00.



Regards


Donal
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Question: Judging High Tide by the Moon
 

Donal wrote:

Just to add to your post, at the
equator I think the moon takes about 12 1/2 hours from rise to set.

I think I pretty-much covered that. :-)

Obviously, Nav didn't read your entire post.

It's true that I didn't explicitly discuss the effect of latitude, although
I did allude to the idea in an earlier post when I suggested that the
principle wouldn't hold at extreme latitudes. (Given the rounded shape of
the earth, it would incorrect to think that there's a hard transition.)


Top marks Wally (for an informative post). I give myself 2/10 for
comprehension, but I will read it again.

It's all about angles and spinny things.


--
Wally
www.forthsailing.com
www.wally.myby.co.uk