Re: "In a Year of 13 Moons"
- From: pausch@xxxxxxx (Paul Schlyter)
- Date: Sat, 11 Nov 2006 10:12:43 GMT
In article <ej2lsm$88g$1@xxxxxxxxxxxxxxxxxxxx>,
Prai Jei <pvstownsend@xxxxxxxxxxxxxxxxxxx> wrote:
John Schutkeker (or somebody else of the same name) wrote thusly in message
<Xns9875A96C8F48Clkajehoriuasldfjknak@xxxxxxxxxxxxxx>:
Until I read the first response, I thought that there were always 13
months in a year. If there are 12 and a fraction months in one, then
every few years that fraction will align just right so that the year
both begins and ends with a new moon (or a full one, if you prefer).
Then there are 13 "moons" in a year.
It's very nearly 12 8/19 lunar months in a year. (Actually a wee bit less,
it was more exact when the Julian calendar was in use.)
One synodic month = 29.530588853 days
29.530588853 * (12 + 8/19) = 366.800998....
29.530588853 * (12 + 7/19) = 365.246756....
A year isn't very nearly 366.8 days..... :-)
Thus the sequence
of new moon dates will repeat every 19 years (228 calendar months, 236
lunar orbits), the so-called "golden number" sequence in which each year is
allocated a number from 1 to 19. The golden number 1 is taken by years
which are multiples of 19, most recently 1995. The year 2006 has the golden
number 12.
The same fraction 8/19 is the reason why the Jewish calendar puts a 13th
month in the year eight times in a 19-year cycle.
--
----------------------------------------------------------------
Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN
e-mail: pausch at stockholm dot bostream dot se
WWW: http://stjarnhimlen.se/
.
- Prev by Date: Re: THE DIVINE DRUDGING DROUGHT BEARING FULLY ON AUSTRALIA NOW
- Next by Date: Re: THE DIVINE DRUDGING DROUGHT BEARING FULLY ON AUSTRALIA NOW
- Previous by thread: Re: THE DIVINE DRUDGING DROUGHT BEARING FULLY ON AUSTRALIA NOW
- Next by thread: Re: NASA Sees Into The Eye of a Monster Storm on Saturn
- Index(es):
Relevant Pages
|
|
