Thales SESO on board of GAIA Telescope

GAIA is a space observatory of the ESA which is going to list approximately 1 billion (109) of components of the universe. Each will be approximately observed 70 times during 5 years of the telescope’s life. GAIA was successfully launched December 19th, 2013 and will reach its point of observation approximately 3 week later.
Gaia is composed by 3 instruments:
- Astro: Instrument which is going to determine the position of every star of the galaxy and by its follow-up over 5 years to evaluate their distance and speed.
- The radial velocimeter to measure more exactly the speed of stars.
- The photometer which measures the star’s luminosity. It has 2 channels blue and red, which allow determining star’s properties as their T°, mass, age and main composition. The spectral bandwidth of the stars’s light is obtained through 2 prisms manufactured by Thales SESO. The blue prism for 330-680 nm spectral bandwidth and red prism 640-1050 nm. Each prism has a useful length of more than 400 mm and is characterized by its very high quality of optical surface (flatness, roughness).

blue and red prisms

Red and Blue photometer prisms

Location of the Red and Blue photometer prisms.
Image courtesy: AIRBUS


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