First goal achieved by ESPRESSO, the next generation planet hunter
The ESPRESSO spectrograph, installed on the Very Large Telescope-VLT in Chile, has succeeded for the first time in combining light from all the four telescopes that compose it, thus making the VLT the world’s largest optical telescope, with a collecting area equivalent to that of a single instrument with a mirror 16 metres in diameter.
This important success for modern astrophysics is the result of the work carried out by an international consortium of researchers led by the Astronomical Observatory of the University of Geneva, which involved Italy through the Astronomical Observatories of the National Institute for Astrophysics of Trieste and Brera.
The VLT is the flagship facility for European ground-based astronomy at the beginning of the third millennium and is composed of four main telescopes (Unit Telescopes: UTs), with primary mirrors 8.2 m in diameter, and four movable 1.8 m diameter telescopes (Auxiliary Telescopes: ATs). The use of the ESPRESSO instrument will allow the four telescopes to work together to observe the sky with unprecedented precision.
The two main scientific goals of ESPRESSO are the discovery and characterization of Earth-like planets and the search for possible variability of the fundamental constants of physics. Both goals can be achieved thanks to the exceptional stability of the instrument and an extremely stable reference light source.
“This impressive milestone is the culmination of work by a large team of scientists and engineers over many years”, said Paolo Molaro, from INAF in Trieste and Scientific Director of the project. “It is wonderful to see ESPRESSO working with all four Unit Telescopes and I look forward to the exciting science results to come”.
A system of mirrors, prisms and lenses will transmit the light from each of the four main VLT telescopes to the ESPRESSO spectrograph, up to 69 metres away. Alternatively, ESPRESSO will be able to collect the light from each of the four telescopes independently, for more flexible usage of observing time.
“ESPRESSO working with all four Unit Telescopes gives us an enticing foretaste of what the next generation of telescopes, such as ESO’s ELT (Extremely Large Telescope), will offer in a few years”, said ESO’s Director General, Xavier Barcons.