Sun and Moon
The ephemerides of the Sun, the Moon and the other bodies of the solar system are calculated and provided by IMCCE (Institut de mécanique céleste et de calcul des éphémérides). The positions and motions of these bodies are necessary for our way of life : they allow to provide the timing of sunsets and sunrises –which are legal regulations- and moonsets and moonrises for any location. They allow also to describe the aspect of the sky, the visibility of the planets and constellations. They also allow to calculate and predict astronomical phenomena such the eclipses of the Sun and the Moon. More, our calendar depends on the positions of the Sun and of the Moon.
The use of ephemerides
The observation and the study of solar system bodies allow to make the ephemerides but bring us knowledge of our planetary environment, of the other planets. Such a study has also an interest going further than the only knowledge of our spacial neibourgh. Observing the motions in the solar system allows us confirming fundamental researches :
- The theory of the general relativity was confirmed thanks to the observation of the motion of the planet Mercury, its too fast perihelion motion being not explained by the Newtonian gravitation;
- Celestial mechanics had a crucial role in the launching of artificial satellites of the Earth essential for the observation of the Earth, of telecommunications and of meteorology;
- Long term study of the evolution of the solar system allows us to know the changes in the orbit of the Earth and their consequences on climate.
Ephemerides for everyone
IMCCE provides ephemerides for all : positions of the planets and of the other bodies of the solar system, timings of their sets and rises for a given site, dates of astronomical phenomena (eclipses of the Moon and of the Sun), and information on the motion of the celestial bodies.
IMCCE provides also very completed ephemerides for the need of space agencies and for the driving of automatic or large telescopes.
IMCCE proposes expertises on the conditions of illumination of the Sun and the Moon everywhere at any time and provides specific ephemerides on request.
To know more about the ephemerides of IMCCE at Paris observatory.