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IAA Transactions, No. 8, ``Celestial Mechanics'', 2002
The ephemerides server of the Institut de m'ecanique
c'eleste et de calcul des 'eph'em'erides
N. Baron, J. E. Arlot
Institut de m'ecanique c'eleste et de calcul des 'eph'em'erides, Paris, France
The Institut de m'ecanique c'eleste et de calcul des 'eph'em'erides
(IMCCE), formerly known as Bureau des longitudes, produces, since its creation
(1795), the French ephemerides for most of the bodies of the solar system. More,
the IMCCE produces ephemerides of stars on the demand of the users.
The IMCCE publishes yearly the Connaissance des temps, founded in 1679
and based upon the most recent dynamical models (original analytical theo­
ries, elaborated in the Institute), the Annuaire du Bureau des longitudes con­
taining ephemerides of small precision for the general public use and Nautical
ephemerides, since 1889, for navigation. Ephemerides of asteroids and comets
are also available through specific Notes Scientifiques et Techniques at IMCCE.
The ephemerides of IMCCE are maintained thanks to research activities in the
area of dynamics, celestial mechanics and astronomy. They lead to elaboration of
theories of motion of the solar system objects.
Along with these publications of ephemerides, IMCCE makes available an
ephemeris server either on the French Minitel network (36 15 BDL) for the general
public use or on an interactive server of ephemerides computation, at the address,
http://www.bdl.fr, available on Internet, to calculate the positions of the solar
system bodies as well as their physical parameters. This Internet server proposes
several services; among them, the ephemerides service provides different types of
ephemerides.
First, the general ephemerides of the solar system provide right ascension and
declination of most of the solar system bodies in any reference frame (heliocentric,
topocentric, planetocentric, geocentric, topographic, horizontal, ecliptic J2000,
apparent, geometric). These ephemerides are available for different theoretical
models such as DE200, DE403, DE405, DE406 and VSOP82, VSOP87 for the
planets.
Second, the ephemerides for physical observations designed especially for the
observers at the surfaces of the objects of the solar system. Longitude of the cen­
tral meridian, planetocentric declinations of the Sun and the Earth are provided
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as well as planetocentric longitudes and latitudes of the sub­earth and sub­solar
points, position angle of the planet North pole, apparent radius, visual magni­
tude, phase angle, distance from the Earth and the Sun, position angle of the
planet intensity equator, apparent configuration of the solar system bodies (plan­
ets, natural satellites, some asteroids). A graphic representation is proposed in
postscript format together with the table of number.
Third, specific ephemerides for the natural planetary satellites are avail­
able: first, equatorial geocentric coordinates as seen above and second, re­
lative ephemerides to the planet in the tangential plane, and geometric rec­
tangular ephemerides.
Fourth, ephemerides for the celestial phenomena are provided. The ti­
mings of sunsets and sunrises and the same for the Moon and the planets are
available for any location on Earth. Eclipses of the Sun and eclipses of the Moon
are predicted for several years, lunar eclipses between 1997 and 2010 and solar
eclipses between 1998 and 2004. Data for calendars, holidays, seasons, phases of
the Moon are also available. Phenomena of the Galilean satellites of Jupiter and
of Saturn are also provided.
Numerous data are available on the FTP server [1] such as ephemerides
under the form of coefficients allowing anyone to build their own epheme­
rides for a specific interval of time and tables; elements of orbits (for asteroids
and comets) allowing anyone to build orbits for these bodies. The code of several
theoretical models is provided.
The ephemerides server displays also data and tools as astronomical data and
parameters for the observation of the solar system objects such as cometary notes
of the IMCCE, astronomical glossary, the StarField Map server and a conversion
between calendar date and Julian date.
Tools for observers are provided for astrometric observations (reduction, etc.)
and for the observation of the phenomena of the natural planetary satellites, es­
pecially for the next campaign of observation of the mutual events of the Galilean
satellites (http://www.bdl.fr/phemu03 eng.html).
References
1. Baron N., Emelianov N. La collecte des observations et le calcul ces
'eph'em'erides, Journ'ees Scientifiques de l'Institut de m'ecanique c'eleste et de
calculs des 'eph'em'erides, 2000.
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