Ground-based astronomy

As a longstanding partner of the French, European and international community of astronomers, Sagem, through its Reosc subsidiary, has continuously met the many technological challenges raised by some of the most ambitious projects. The aim: supply the best state-of-the-art components, equipment or subsystems worldwide.


Founded by Henri Chrétien and Charles Fabry, Reosc has developed its activity in optics for earth-based astronomy based on know-how unique the world over. Ranging from research and design to production and integration, Reosc currently offers a complete range of high-performance optics and high-precision opto-mechanical equipment.

Drawing on its experience in all the fields of optics, Reosc develops and produces large 4- to 8-m class monolithic mirrors, primary mirror segments for very large instruments and “turnkey” telescope systems including telescopes, domes, control-command systems, maintenance equipment and civil engineering.

Reosc also supplies opto-mechanical equipment, field correctors, atmospheric dispersion compensators as well as corrector lenses and filters for wide-angle cameras.

Lastly, Reosc meets the strictest requirements set by a great number of institutions, undertaking the development of innovative astronomy instruments and the production of all the optical subassemblies or components (lens, aspheric mirrors) based on specifications or custom-designed.

A key player in major international scientific programs, Reosc has produced mirrors including the 8-m monolithic mirrors for the Very Large Telescope in Chile, the 11-m mirror for the GTC Gran Telescopio de Canarias and the mirror prototypes for the future 42-m European - Extremely Large Telescope (E-ELT).

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