Sun and Moon

The ephemerides of the Sun, the Moon and the other bodies of the solar system are calculated and provided by LTE. 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

LTE provides ephemerides for all: positions of the planets and other solar system bodies, times of their rising and setting at a given location), dates of astronomical phenomena in particular lunar and solar eclipses, as well as information on the motion of the stars.
LTE also provides comprehensive precise ephemerides for astronomers, space agencies and large telescope pilots.
The LTE also provides expert reports on the illumination conditions of the Sun and Moon at any given location.