The Institut de mecanique celeste et de calcul des ephemerides provides and publishes ephemerides of solar system bodies. It serves as the official and public source of ephemerides devoted to regulate calendars.

It performs theoretical research activities in the fields of celestial mechanics, planetology and mathematics. It initiates and coordinates observing campaigns of rare and specific celestial events.
 

The lost light of Kalliope

The asteroid Kalliope (22), some 170km wide, has a small satellite into orbit, Linus, with much smaller dimensions. Kalliope is what is called a binary asteroid . This system is part of the main belt of asteroids and is currently at a distance equivalent to over twice the Earth-Sun distance. Seen from Earth, it is not bigger than a two euro coin placed at 45km! In other words, we do not see it , but instead it can be detected through the small amount of sunlight - one million times smaller than Venus' light at its maximum brightness - coming back to us. However, for astronomers, it is called brilliant , a telescope of only 20cm in diameter - can collect 1,000 times more light than the pupil of the eye - is enough to reveal it.

Throughout the month of February 2012, this system will show himself by its best angle, edge-on. In other words, mutual eclipses will take place as the Sun and the system of Kalliope share the same plane in space, it will be the time of the equinox on Kalliope. What does this mean ? A slight loss of light from the global system for nearly two hours, the duration of an eclipse of Kalliope. These micro disappearance of light on Earth can be observed preferably from the northern hemisphere where Kalliope is high in the sky.

More about:
Kalliope's page

Simulation of the eclipse of Kalliope by Linus March 2, 2012

 

Agenda 2012

For several years, the Observatoire de Paris and IMCCE publish this unique astronomical calendar.
Explore the sky until these distant galaxies, read about the scientific advances that have revealed the mysteries of the universe, find these men and women who have pushed the boundaries of knowledge! You will also find, this year, the latest advances in radio astronomy.

L'observatoire de la marine et du Bureau des longitudes au parc Montsouris 1875-1914

Why a marine observatory in Paris, in Parc Montsouris?

The answer is contained in this story, so far forgotten, that Guy Boistel has patiently reconstructed from the extensive archives of the Bureau des Longitudes, among others.

Caution : This Website was created with the Ministère de l'Education Nationale, the CNRS and the CNES support. Any use of the data published on this website requires the IMCCE agreement..