Hi Hendrik,
Paul de Kort is a good artist and he makes exceptional artworks and
design.
When he involves the sciences astronomy and astrology in his work he
hits the wrong ball, however.
A sundial is primarily a scientific instrument. The zodiac is a
scientifically determined reference system.
A "constellation of the zodiac" is a nonexistent concept. A
"constellation of stars" exists. A "zodiac sign" exist too. He (and
you) confuses the two.
And therefore, what he wrote in the brochure about the park in the
suburb Saendelft in Zaanstad, is nonsense.
He wrote:
"In several thousand years, the signs of the zodiac are shifted from
the position of the Earth and the Sun
We also see that the sun is not exactly during one month in a given
sign, such as astrology says, deluding us.
This varies from sign to sign and a few days to almost one and a half
month.
And when you are born in early December, you are born under the sign
of Ophiuchus, the 13th sign! "
Astrology and astronomy doesn't have differences in their definition
of ecliptic and Vernal Equinox or the location of constellations,
zodiac signs, sun, moon and planets in the ecliptic.
It is a big misconception that astrologers place their reference
system in the stars and do'nt take account of the precession.
In the reference system of astrologers the precession is not useful.
Stars and constellations do'nt have a place in it.
Even if there were no stars the astrology would still have its
reference system.
It consists of a system of positioning in the the ecliptic, starting
from the vernal equinox, divided into 12 equal parts. In this system
the position of the sun, moon and planets are projected, as seen from
the Earth.
Their place in the ecliptic (at a given time, the birth a person for
example) and how they interrelate (opposite each other, overlapping,
in angles of 150, 120, 90, 60 and 30 degrees) is the underlying
pattern that astrologers use.
I simplify here, not talking about the Ascendant.
I am not talking about the statements by astrologers based on this
reference system.
That is because it is outside the domain of astronomy.
Willy LEENDERS
Hasselt in Flanders (Belgium)
Visit my website on the sundials in the province of Limburg in
Flanders (Belgium) and on worthwhile facts about sundials
www.wijzerweb.be
Op 23-dec-2009, om 8:45 heeft Analemma zonnewijzers het volgende
geschreven:
Hi All,
This reminds me of a sundial, made by Landscape artist Paul de Kort
in Zaanstad/The Netherlands. For dialing usually the zodiac-signs
are defined as 30 degrees of the ecliptica. However, the true sun
will pass the 12 constellations of the zodiac and also the
constellation Ophiuchus (dutch: 'slangedrager'). Paul did make a
sundial in which this 13th 'zodiac'-constellation is incorporated.
Very nice.
for more work of Paul see: www.pauldekort.nl
for the sundial, see (page 6): http://www.pauldekort.nl/
_backgrounds/getijdenpark%20BROCHURE%20lowres.pdf
kind regards,
Hendrik Hollander
--------------------------
Analemma zonnewijzers
Hendrik Hollander
tel: 020 637 43 83
mob: 06 16 462 879
www.analemma.nl
www.linkedin.com/in/hendrikhollander
--------------------------
lees de disclaimer:
www.analemma.nl/maildisclaimer.htm
--------------------------
----- Original Message -----
From: "Bill Gottesman" <billgottes...@comcast.net>
To: <sundial@uni-koeln.de>
Sent: Tuesday, December 22, 2009 4:51 PM
Subject: Re: zodiac lengths
Well done, Frank!
-Bill Gottesman
Frank King wrote:
> Dear Thomas,
>
> You ask interesting questions and the
> answers depend slightly on just how
> precisely you want the model the way
> the sun goes round the ecliptic.
>
> QUESTION 1
>
> ... do [Gemini and Cancer] share
> *exactly* the same region [on a
> sundial] or not?
>
> I think it is reasonable to DEFINE
> the 12 regions of the Zodiac as being
> bounded at 30-degree intervals of
> solar *longitude*. So Aries extends
> from 0 to 30 and so on.
>
> On the ecliptic, these 12 regions are
> distinct and there is no sharing.
>
> When you look at the corresponding
> intervals of solar *declination*
> you do, as you say, get sharing.
>
> In your example:
>
> Sign Longitude Declination
> range range
>
> Gemini 60 to 90 20.15 to 23.44
>
> Cancer 90 to 120 23.44 to 20.15
>
> As you see, Gemini and Cancer share the
> same range of declinations but for Gemini
> the declination is increasing and for
> Cancer is decreasing.
>
> The answer to your question is YES.
>
> So far, this theory has nothing to do with
> the *shape* of the Earth's orbit but it does
> assume that the orbit is a plane which is
> isn't exactly.
>
> [Solar latitude hovers around zero but it
> isn't exactly zero. A REALLY pedantic
> discussion about whether Gemini and Cancer
> exactly overlap would take a book!]
>
> You then ask about dates. That makes the
> story very much more complicated but it
> doesn't stop Gemini and Cancer sharing
> the same region on a sundial.
>
> QUESTION 2
>
> Is the starting date May 20 of one in line
> with the end-date July 22 of the other or not?
>
> You go too fast. Who says the starting date
> is May 20? It sometimes is and it sometimes
> isn't. You have to worry about the leap-year
> cycle and Pope Gregory XIII and his friends.
>
> At the moment we are living close to the middle
> of an almost 200-year run of pure Julian
> calendar. There are no omitted leap-years
> between 1904 and 2096 inclusive. This means
> there is a steady drift in all the dates you
> are interested in.
>
> The starting *declination* of one IS in line
> with the ending *declination* of the other but
> when you worry about dates everything becomes
> harder.
>
> The only sensible answer to this second
> question is NO. It is no because the dates
> change from year to year. See the answer
> to Question 4, but first...
>
> QUESTION 3
>
> The angles of the ecliptic longitude for
> the zodiacs are equally distributed (each 30°),
> [YES that's right] but what about the angles
> in the earth's orbit around the sun (ellipse)?
>
> I don't quite understand this. The ecliptic
> longitude is the same as the angle of the Earth's
> orbit round the sun (though you might want to
> change the sign or add 180 degrees).
>
> The answer is THEY ARE THE SAME.
>
> QUESTION 4
>
> And what about the dates?
>
> They are horrible! I have already said there is
> a steady drift in the dates but it is worse than
> that because of the precession of the equinoxes.
> The answer is THE DATES ARE A MESS and...
>
> QUESTION 5
>
> The lengths (in terms of time) of the zodiacs
> are not equal, but are they constant each year?
>
> The answer is UNFORTUNATELY NO. It is easy to
> see that they are not constant by thinking about
> this time of year. We have just entered the
> sign of Capricorn and at this time of year the
> Earth is closest to the sun.
>
> That's good news because it gets winter over
> quicker. Capricorn doesn't last long! Also,
> this explains why the lengths are not constant.
>
> Unfortunately, there will come a time when we
> are furthest from the sun in winter. Capricorn
> will take longer and we could find the northern
> hemisphere covered in ice.
>
> [ There will then be conferences about trying to
> raise the levels of carbon dioxide :-) ]
>
> QUESTION 6
>
> Can anybody give me a better reference than
> Wikipedia...
>
> The best thing you can do is to ask your girlfriend
> to buy you a copy of "Astronomical Algorithms" by
> Jean Meeus as a Christmas present. You can then
> write a proper program to model the Earth-Sun
> system. It took me about 2000 lines of code before
> I was happy with it but it is a very good way of
> answering your questions!
>
> Best wishes
>
> Frank
>
>
> ---------------------------------------------------
> https://lists.uni-koeln.de/mailman/listinfo/sundial
>
>
>
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