In 1969, Raymond Michard, an astronomer at the Paris Observatory, and Lloyd Evans observed the Sun to study the eruption phenomenon. During their observations, they detected strange movements, which seemed to be periodic.
In 1970, these observations were confirmed by Leighton (USA).
The sismology of the Sun was born.
Do other stars vibrate?
In 1984, a first meeting at the Paris Observatory gathered about 50 French researchers and some foreign colleagues. At this time, the first ideas for a project focused on the observation of the variability of the stars in space were formed.
For the design of the instrument it was required to :
Space exploration is expensive and the competition is rough : between 1984 and 1989 several propositions were presented, without success, but the relentless work of the LESIA and the Laboratory of Astronomy at Marseille was finally rewarded.