Just to clarify. The prime meridian of
Paris (and of France and of French maps, etc.)
was the one at l'Observatoire de Paris from late
17th c onwards. Any other meridians were "local",
including St. Sulpice, which, alas, has now lost
some of its joy for me (I've made many
observations of transit over the past decade) now
that it's been trivialized and is inundated by
tourists...similar to Strauss's "Also Sprach
Zarathrusta" after the "2001: A Space Odyssey"
movie came out in the late 1960s.
- Woody
P.S. Thanks for the nice URL with the listing of
all the Arago medallions. I think I see the
makings of a long day hunting them down the next
time I'm in Paris!
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At 18:02 -0800 12/16/04, Roger Bailey wrote:
Bonjour François and all,
I have a suggestion and some web links on solar alignments. A church
meridian of great interest these days is the meridian in Eglise
Saint-Sulpice in Paris. See the description at
http://www.paris-pittoresque.com/monuments/41b.htm
"L'église Saint-Sulpice possède encore des richesses d'un autre genre.....
l'obélisque en marbre blanc, haut de plus de 8 mètres, construit à usage de
méridien par Sully et Lemonnier en 1773, pour fixer d'une manière certaine
l'équinoxe du printemps et le jour de Pâques."
See the full description at http://www2.iap.fr/saf/csmp/arr6n/centrea64.html
The Saint-Surplice meridian is a key element in the best selling novel "The
Da Vinci Code" by Dan Brown. This novel describes the meridian as follows,
"Long before the establishment of Greenwich as the prime meridian, the zero
longitude of the entire world had passed directly through Paris, and through
the Church of Saint-Sulpice. The brass marker in Saint-Sulpice was a
memorial to the world's first prime meridian, and although Greenwich had
stripped Paris of the honour in 1888, the original Rose Line was still
visible today."
Pictures of the brass strip and gnomon of the meridian are at this website:
http://www.davidphenry.com/Paris/da-Vinci-Code-Paris.htm
This confused me as I expected the Paris Meridian to go through the
Observatory of Paris at the south end of the Jardin du Luxembourg. It does.
The current Paris Meridian, marked through Paris with brass Arago
Medallions, passes through the Observatory and is about 150 meters to the
east of the Saint-Sulpice meridian. The meridians are quite different but
the novel brings them together. This is not the only fact embellished by the
author to set the plot for his novel.
See http://www.parissweethome.com/parisrentals/art_fr.php?id=31 for the
locations of the Arago Medallions. For the Paris Observatory see
http://www.paris-pittoresque.com/monuments/35b.htm "Rappelons seulement que
le méridien de Paris, tracé dans la grande salle du second étage, divise
l'édifice en deux parties par une ligne qui, prolongée du sud au nord,
s'étend d'un côté jusqu'à Collioure, sur la Méditerranée, et de l'autre
jusqu'à Dunkerque, sur la mer du Nord. Ces deux lignes, qui se coupent au
centre de la façade, ont servi de base aux nombreux triangles d'après
lesquels ont été levées au siècle dernier la carte générale de la France
appelée carte de Cassini, et, dans le milieu du présent siècle, la carte
dite de l'état-major, commencée sous la direction du général Pelet."
My conclusion is that there are several Paris Meridians, built at different
times for different purposes: At Saint-Sulpice, the Sully Meridian to set
clocks and watches, and the Lemonnier Meridian to deternine the solstices,
equinoxes and date of Easter; At the Observatory, the Cassini / Arago
meridian to act as the Prime Meridian as Paris is the Centre of the
Universe, to establish a base line for maps. There is also the
Delambre/Méchain Meridian described in the book "The Measure of All Things".
This survey to measure the world and define the meter used the Pantheon as
the triangulation base for a meridian passing to the east, perhaps through
the Bastille. Then there is the brass disc in front of Notre Dame which is
not on any of these meridians. This disc is said to mark the centre of Paris
and France and to be the base point for maps.
I remain confused. Which is the true Paris Meridian? When I visited the
Paris sites, I didn't get the same experience as you get straddling the
prime meridian at Greenwich, with one leg in the eastern and the other in
the west.
--
******************************************************************
Prof. Woodruff T. Sullivan, III Center
for Astrobiology & Early Evolution
Dept. of Astronomy Box 351580
Univ. of Washington tel. 206-543-7773
Seattle, WA 98195 USA fax 206-685-0403
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