Greetings, fellow dialists,
Re the question concerning the day on which the sun sets at the same
moment in London and Paris, the following solution was offered by a sea
captain, long retired, of my acquaintance (we were shipmates in 1944).
Here he uses the tools of his trade (mostly tables) to
Dear Warren,
Happy Summer Solstice!
You ask an astute question:
Are you saying below that ANY two locations MUST
have a moment of mutual sunrise/sunset?
Well, I am ALMOST saying that and the mathematics
IS saying that...
The declination of the sun is, of course, constrained
to be between
Dear Frank et al,
After a second night sleeping on your nice puzzle I
realised that I DID make a small goof in one of my
assertions and no one has picked me up on it!!
In the formula:
tan(dec) = [-]sin(d)/sqrt(t1^2 - 2.t1.t2.cos(d) + t2^2)
I asserted (correctly) that the argument of the square
Dear Mr. King,
I have really enjoyed this problem. In one sense it is simple because it
not about hours, but about events.
In a recent post you said:
From: Frank King
Subject: Re: simultaneous sunset
One of the many nice features of this puzzle is that there
is no need to know the time
Warren and others,
After installing Sun Clock which can be found on www.mapmaker.com you
can easily see that there is a whole range of locations on the earth
with different longitudes where the sun sets simultaneously. A
picture tells us sometimes much more then a story.
Thibaud Chabot
At
Dear Frank et al,
An intriguing side issue to your puzzle is that
it relates to the discussion about the Hawkeshead
dial and the notion of a Plane's Longitude and,
implicitly, the notion of a Plane's Latitude.
Once you have taken on board these notions, the
simplest way of expressing the
Greetings, fellow dialists,
So many clever solutions! I am no mathematician but I suppose I am in
duty bound to add my two pennyworth to the sunset problem. If 90 deg is
added to the angle Pole-Paris-London (obtainable from given) then this
angle is the internal angle of Pole-Paris-Sun. The
Hello Franks and all,
I assume we are to neglect altitude differences and use the fictional
spherical earth model, but just what do we mean by 'the same time'? I
would assume that when two or more persons look at their watches,
corrected for standard zone time, that they read the same
Hello Edley and listeners everywhere,
Edley, I don't quite know how to answer you. I explained in an earlier
message that this was a real question set for airline pilots but it was
fifty eight years ago and the exact wording unfortunately eludes me. Did
they have nanoseconds then? And what
Greetings, fellow dialists,
A little while ago there was a dialling discussion about pairs of places
where the sun rose or set at the same moment. I recall that to solve the
problem a terminator programme was called into play.
There are earlier examples of this question. Around the year 1950
Dear Frank,
I do enjoy your puzzles!!
... a question appeared of the form:
Find a day on which the sun sets (altitude 0 deg.) at
the same moment in London and Paris (positions given).
Conceptually this is trivial. Mathematically it gets a
little messy but I think I can get a closed form
Of Frank King
Sent: Monday, June 18, 2007 7:20 PM
To: Frank Evans
Cc: Sundial
Subject: Re: simultaneous sunset
Dear Frank,
I do enjoy your puzzles!!
... a question appeared of the form:
Find a day on which the sun sets (altitude 0 deg.) at
the same moment in London and Paris (positions given
Message -
From: Frank King [EMAIL PROTECTED]
To: Frank Evans [EMAIL PROTECTED]
Cc: Sundial [EMAIL PROTECTED]
Sent: Monday, June 18, 2007 11:20 AM
Subject: Re: simultaneous sunset
Dear Frank,
I do enjoy your puzzles!!
... a question appeared of the form:
Find a day on which the sun sets
Evans
[EMAIL PROTECTED]
Cc: Sundial [EMAIL PROTECTED]
Sent: Monday, June 18, 2007 6:59 PM
Subject: RE: simultaneous sunset
Dear Frank,
It is not really possible to tidy up your efforts, because I think they
are as clean as they can possibly be - but I can try to mess up your
efforts by another
14 matches
Mail list logo
