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Old January 31st 18, 05:17 PM posted to uk.sci.astronomy
Martin Brown[_3_]
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Posts: 189
Default Of moon and tides

On 31/01/2018 14:16, N_Cook wrote:
A quirk of celestial mechanics.
As the last blood-red , blue-moon, super-moon was 31 March 1866 we'll
have to wait 55458 days for the next coincidence of the tides in the
channel , presumably.
I wonder what conjuction of tidal harmonics gives a 55,458 day repeat.


It is double the named "Short Callipic Cycle" 2I+S = 75.9y 27729.22d

27729.22 x 2 = 55458.44 but according to the catalogue is unnamed.

I = Inex ~29y and S = Saros ~18y

They are the fundamental periodicities that allow you to catalogue
eclipse cycles. It will be interesting to see if the strong tides this
year drive any climatic effects from deep ocean mixing.

http://www.staff.science.uu.nl/~gent...ipsecycles.htm

Inex gives you an eclipse about the same longitude but opposite latitude
and 3x Saros gives you about the same eclipse conditions in about the
same place on the Earth. Or for an overviews and better explanation

https://eclipse.gsfc.nasa.gov/SEsaro...riodicity.html

The high tides in ports of a large part of the English channel today are
all the same time. I originally thought there was a problem with big-data
http://www.ntslf.org/storm-surges/la...ast?port=Dover
http://www.ntslf.org/storm-surges/la...?port=Newhaven
http://www.ntslf.org/storm-surges/la...ort=Portsmouth

And from the UK Hydrographic office, high tide times today
Portsmouth,10:53,Â*Â*Â* 23:24
Newhaven, 10:43Â*Â*Â* ,Â*Â*Â* 23:17
Dover, 10:44,Â*Â*Â* 23:09



--
Regards,
Martin Brown