The Space Service
of the Paris Observatory

The Space Service of the Paris Observatory (SE-OP) is the service of the Paris Observatory assigned to the Laboratoire Temps Espace (LTE), responsible for space metrology activities. It brings together activities related to ephemerides, Earth rotation and reference frames.

Missions

The Space Service of the Paris Observatory (SE-OP) is responsible, under the authority of the Paris Observatory and under the auspices of the Bureau des Longitudes, for compiling and disseminating ephemerides of Solar System objects and calendars. It is the official public national source of ephemerides.

This societal mission, entrusted by the French State to the Paris Observatory, is carried out by the SE-OP teams, who implement research and associated technologies in order to offer a range of services accessible to public and private actors as well as citizens. In this context, the SE-OP has several missions:

• develop high-precision solutions for planetary ephemerides and the dynamics of bodies of the Solar System (Sun, Moon, planets, dwarf planets, satellites and other small bodies);
• produce official publications and editions each year;
• disseminate ephemerides of various bodies of the Solar System and celestial phenomena;
• provide legal expertise to the courts;
• provide ephemerides and data on request for similar services (United States of America, Japan), agencies, researchers, laboratories and observatories.

The SE-OP takes over and continues the missions of the Institut de mécanique céleste et de calcul des éphémérides (IMCCE) which merged with the Système de référence temps-espace laboratory (SYRTE) to form the LTE.

Service Activities

In addition to producing publications and distributing ephemerides in various forms, the SE-OP performs specific astronomical calculations for various public and institutional users. These calculations are performed on request of administrative bodies such as the police, courts, insurance companies, architects and filmmakers, or on behalf of scientific organisations such as astronomical observatories and space agencies.

The SE-OP also offers the general public, amateur astronomers and associations the opportunity to contact it with any queries relating to ephemerides, celestial phenomena and calendars.

Space and Instrumental Activities

The SE-OP has long been strongly involved in space research, both upstream and downstream of space missions, as well as in the implementation of data processing pipelines. Owing to its expertise, it is a key partner for public and private space agencies and consortia.

It is particularly involved in projects run by the Centre national d’études spatiales (CNES), European Space Agency (ESA – Gaia, Juice…) space missions to explore the Solar System and data processing pipelines for major international instrumental projects (Gaia, Vera C. Rubin Observatory…).

Research

Research at the SE-OP is conducted in the fields of celestial mechanics, in both its mathematical and dynamical aspects, astrometry, and planetary science. It is carried out within the framework of the work of five scientific teams from the Laboratoire temps espace.

Observation Facilities

Much of the SE-OP's research work is based on observation – the foundation of all astronomical studies. The SE-OP has its own observation facilities.

National Observation Services

The SE-OP members operate or participate in national observation services (SNO) labelled by the Institut national des sciences de l’Univers (INSU):

• ANO1 – Time and space metrology
  • Gaia
  • ICRS-PC (International Celestial Reference System Product Center)
  • IERS_EOP-PC (International Earth Rotation et Reference Systems Service, Earth Orientation Parameter Product Center)
  • ILRS (International Laser Ranging Service)
  • IVS (International VLBI Service for Geodesy and Astrometry)
  • Service des éphémérides
  • Stations de télémétrie laser
• ANO4 – Large-scale surveys, deep probing, and long-term monitoring and support
  • Gaia
• ANO5 – Centres of data processing, archiving and dissemination
  • Paris Astronomical Data Centre
  • VO Solar System Objects Portal
• ANO6 – Monitoring the Sun and the Earth's space environment
  • FRIPON