Of moon and tides

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.

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, 23:24
Newhaven, 10:43 , 23:17
Dover, 10:44, 23:09

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.

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, 23:24
Newhaven, 10:43 , 23:17
Dover, 10:44, 23:09

Hydrographic Office EasyTide “predictions" for 31st March 1866…

Portsmouth times LW=04.40 HW=1129 LW=1658 HW=2353
Dover times Lw=0640 HW=1126 LW=1854 HW=2342

so once in a blood-red , blue-moon, super-moon

Now to find out any significance in
55458= 13x54x79
or in terms of 18.61 year or 8.85 year normal tide cycles

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

On 31/01/2018 16:17, Martin Brown wrote:
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, 23:24
Newhaven, 10:43 , 23:17
Dover, 10:44, 23:09



Ta for that, I'll let the local NOC academic oceanographers know, to
avoid too much head-scratching.
Next stop Milankovitch cycles

On 31/01/2018 18:03, N_Cook wrote:
On 31/01/2018 16:17, Martin Brown wrote:
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

Ta for that, I'll let the local NOC academic oceanographers know, to
avoid too much head-scratching.
Â*Next stop Milankovitch cycles

Checking there was also a nice juicy total lunar eclipse in 1942 Mar 3
which is midway between the one you quoted and now (ie every 2I+S).

https://en.wikipedia.org/wiki/March_1942_lunar_eclipse

Any interesting tides observed back then?

The one later in the year promises to have better UK visibility but we
still won't see totality well - moon will rise in eclipse for the UK:

https://www.space.com/33786-lunar-eclipse-guide.html

Some of these empirical eclipse rules have been known since Babylonian
times! Predicting solar eclipses was a blood sport in the early days of
colonising China when Ferdinand Verbiest nearly got killed before
inflicting that fate on the indigenous lazy court "astronomers".

https://en.wikipedia.org/wiki/Ferdin...onomy_contests

Enjoy! Sometimes truth is stranger than fiction.

--
Regards,
Martin Brown

On 31/01/2018 20:29, Martin Brown wrote:
On 31/01/2018 18:03, N_Cook wrote:
On 31/01/2018 16:17, Martin Brown wrote:
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

Ta for that, I'll let the local NOC academic oceanographers know, to
avoid too much head-scratching.
Next stop Milankovitch cycles

Checking there was also a nice juicy total lunar eclipse in 1942 Mar 3
which is midway between the one you quoted and now (ie every 2I+S).

https://en.wikipedia.org/wiki/March_1942_lunar_eclipse

Any interesting tides observed back then?

The one later in the year promises to have better UK visibility but we
still won't see totality well - moon will rise in eclipse for the UK:

https://www.space.com/33786-lunar-eclipse-guide.html

Some of these empirical eclipse rules have been known since Babylonian
times! Predicting solar eclipses was a blood sport in the early days of
colonising China when Ferdinand Verbiest nearly got killed before
inflicting that fate on the indigenous lazy court "astronomers".

https://en.wikipedia.org/wiki/Ferdin...onomy_contests

Enjoy! Sometimes truth is stranger than fiction.


I doubt anything noticed 1942, any more than generally this week.
Its only the heights that are generally noticed and they are perfectly
normal spring tides this week and this year.
As part of local marine flooding potential, I daily look at NTSLF surge
plots for Pompey, Newlyn and Dover.
Superimposed on the plots is the high tide times ,only, not low tides,
graphically. So it was obvious to the resolution of the plots the times
were the same, highly odd and seemingly in error, Newhaven showed the
same times.
Normally, springs and neaps, the tide pulse goes west to east about 6
hours Newlyn too Pompey and 6 hours Pompey to Dover, where it just about
coincides with the tide pulse down the east coast.

On 01/02/2018 08:45, N_Cook wrote:
On 31/01/2018 20:29, Martin Brown wrote:
On 31/01/2018 18:03, N_Cook wrote:
On 31/01/2018 16:17, Martin Brown wrote:
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

Ta for that, I'll let the local NOC academic oceanographers know, to
avoid too much head-scratching.
Next stop Milankovitch cycles

Checking there was also a nice juicy total lunar eclipse in 1942 Mar 3
which is midway between the one you quoted and now (ie every 2I+S).

https://en.wikipedia.org/wiki/March_1942_lunar_eclipse

Any interesting tides observed back then?

The one later in the year promises to have better UK visibility but we
still won't see totality well - moon will rise in eclipse for the UK:

https://www.space.com/33786-lunar-eclipse-guide.html

Some of these empirical eclipse rules have been known since Babylonian
times! Predicting solar eclipses was a blood sport in the early days of
colonising China when Ferdinand Verbiest nearly got killed before
inflicting that fate on the indigenous lazy court "astronomers".

https://en.wikipedia.org/wiki/Ferdin...onomy_contests

Enjoy! Sometimes truth is stranger than fiction.


I doubt anything noticed 1942, any more than generally this week.
Its only the heights that are generally noticed and they are perfectly
normal spring tides this week and this year.
As part of local marine flooding potential, I daily look at NTSLF surge
plots for Pompey, Newlyn and Dover.
Superimposed on the plots is the high tide times ,only, not low tides,
graphically. So it was obvious to the resolution of the plots the times
were the same, highly odd and seemingly in error, Newhaven showed the
same times.
Normally, springs and neaps, the tide pulse goes west to east about 6
hours Newlyn too Pompey and 6 hours Pompey to Dover, where it just about
coincides with the tide pulse down the east coast.


From one of the NOC experts on deep-sea oceanography
"I would be very surprised if the tides have any significant effect on
deep ocean mixing."
"tides" in this context referring the recent anomolous tides as
exemplified at Dover last week

On 31/01/18 14:16, N_Cook wrote:
A quirk of celestial mechanics.
[...]
The high tides [...].

Nothing directly to do with this [interesting] discussion,
but the BBC's programme on the supermoon was trying to explain what
was meant by full/new/quarter Moon, why some were "super", etc.,
the usual stuff. In the middle of which they told us that when the
Moon was new, its pull reinforced that of the Sun, and we had higher
tides than usual. Nothing said directly, but any normal listener
would have inferred that when it was full, and its pull was opposed
to that of the Sun, tides would be lower. I've heard physicists,
who really should know better, say exactly that on TV.

In trying to explain this to people, they can usually accept
that we get "spring" tides when the Moon-tide and the Sun-tide are
reinforcing each other, and "neap" tides when they oppose. The hard
part is explaining why the Moon-tide bulges both towards and away
from the Moon. You can explain till you're blue in the face that the
Moon's gravity pull is stronger on the side of Earth facing the Moon
and weaker on the side facing away, so the water piles up [a little!]
on both sides, but somehow that gets confused with ellipses with the
Earth at one focus, and/or with the phase of the Moon.

I had one former colleague, a highly intelligent and competent
pure mathematician, who came to me regularly to explain this. "We
did this last year!" "Yes, but I've forgotten, and the children have
asked again, and anyway [famous name] was on TV and his explanation
was different. Surely we get lower high tides at full Moon?" "No,
because [blah]." "No, you've lost me. Are you saying that [name]
was wrong?" "Yes. Let's try again ...."

--
Andy Walker,
Nottingham.

On 05/02/2018 11:52, Andy Walker wrote:
On 31/01/18 14:16, N_Cook wrote:
A quirk of celestial mechanics.
[...]
The high tides [...].

Nothing directly to do with this [interesting] discussion,
but the BBC's programme on the supermoon was trying to explain what
was meant by full/new/quarter Moon, why some were "super", etc.,
the usual stuff. In the middle of which they told us that when the
Moon was new, its pull reinforced that of the Sun, and we had higher
tides than usual. Nothing said directly, but any normal listener
would have inferred that when it was full, and its pull was opposed
to that of the Sun, tides would be lower. I've heard physicists,
who really should know better, say exactly that on TV.

In trying to explain this to people, they can usually accept
that we get "spring" tides when the Moon-tide and the Sun-tide are
reinforcing each other, and "neap" tides when they oppose. The hard
part is explaining why the Moon-tide bulges both towards and away
from the Moon. You can explain till you're blue in the face that the
Moon's gravity pull is stronger on the side of Earth facing the Moon
and weaker on the side facing away, so the water piles up [a little!]
on both sides, but somehow that gets confused with ellipses with the
Earth at one focus, and/or with the phase of the Moon.

I had one former colleague, a highly intelligent and competent
pure mathematician, who came to me regularly to explain this. "We
did this last year!" "Yes, but I've forgotten, and the children have
asked again, and anyway [famous name] was on TV and his explanation
was different. Surely we get lower high tides at full Moon?" "No,
because [blah]." "No, you've lost me. Are you saying that [name]
was wrong?" "Yes. Let's try again ...."


Brian Cox did an excellent visual-aided correct explanation of why
springs occur at new and full moons, and tidal "bulge" on opposite sides
of the Earth at any one time. A few months back on BBC something,
perhaps on Utube if not replayer.
Something to do with momentum/centrepetal forces I seem to remember

On 05/02/18 14:48, N_Cook wrote:
Brian Cox did an excellent visual-aided correct explanation of why
springs occur at new and full moons, and tidal "bulge" on opposite
sides of the Earth at any one time. A few months back on BBC
something, perhaps on Utube if not replayer.

Perhaps "Forces of Nature"? See

https://www.youtube.com/watch?v=4UZxzyOVJ8Q

He has a somewhat different version from "Stargazing" at

https://www.youtube.com/watch?v=WGKgKayuC2M [1]

and I expect there are others. Neither of these really explains
spring/neap, though, AFAIR, nor why the Moon is more important
than the Sun for this purpose.

Something to do with momentum/centrepetal forces I seem to remember

On the other hand, for whether he is correct, people should
perhaps look at the first half of

https://www.youtube.com/watch?v=pwChk4S99i4

Food for thought!

[1] Just seen your other article! But I'll let this one stand anyway.

--
Andy Walker,
Nottingham.