ESPRESSO has its first light on the four telescopes of the VLT at the same time

ESPRESSO instrument, installed in ESO's Very Large Telescope in Chile, has for the first time used the combined light of its four 8.2-metre telescopes. Currently, in terms of light collecting area, combining the telescope units in this way makes the VL
Advertised on
Rueda Moral

When the set of telescopes which make up the VLT was designed, one of its objectives was to be able ot use the four Unit Telescopes (UT) simultaneously as a single giant telescope with an equivalent diameter of 16m. This exceptional configuration has been used for the first light of the ESPRESSO spectrograph, and instrument designed to discover and characterize planets similar to Earth, and to look for variability in the fundamental constants of physics.

The experiments which will be carried out to look for the variability in these constants will gain most benefit from the enhanced light gathering power of the four units of the VLT, because for this project it is necessary to observe distant, faint quasars. In either case, both scientific aims depend on an extremely stable instrument, and an extremely stable reference source of light. “ESPRESSO, together wil the four telescopes of the VLT, will open a new horizon in astronomy, from the study of quasars in the very distant univers to the detection and characterization of exoplanets similar to the Earth” explains Rafael Rebolo, director of the IAC, and one of the codirectors of the project.

Because of its complexity until now the combination of the four UT in the mode utilized by EPRESSO had not been put in action. However during the construction space was left, and the subterranean structure was made in which ESPRESSO has now been placed, and which collects, from a distance of over 69 metres, all the light received  separately by each telescope, thanks to a system of mirrors, prisms, and lenses.

Sending the combined light to a single instrument is unprecedented in astronomy using high resolution spectrographs. “ESPRESSO will allow us to obtain spectroscopic measurements at high resolution with an accuracy and repeatability higherto unachievable, thanks to the use of a laser frequency comb” explains Jonay González Hernández, a Ramon and Cajal Fellow at the IAC and a member of the scientific team of the ESPRESSO project.

ESO press release:

Other press releases:

First light of ESPRESSO: a new generation of hunters for Earth-like planets

Related projects
Projects' name image
Exoplanets and Astrobiology

The search for life in the universe has been driven by recent discoveries of planets around other stars (known as exoplanets), becoming one of the most active fields in modern astrophysics. The growing number of new exoplanets discovered in recent years and the recent advance on the study of their atmospheres are not only providing new valuable

Pallé Bago
ESPRESSO data flow in operations: results of commissioning activities

ESPRESSO, the next generation ESO VLT high-resolution ultra-stable spectrograph, after the successful Preliminary Acceptance Europe held at the integration site of the Observatory of Geneva, has been re-integrated at Paranal and started its commissioning activities at the end of 2017. One critical aspect for ESPRESSO future operations, compared

Di Marcantonio, P. et al.

Advertised on:

ESPRESSO: design and analysis of Coudé-Train concepts for stable and efficient optical feeding

The first purpose of ESPRESSO is to develop a competitive, innovative high-resolution spectrograph to fully exploit the potentiality of the Very Large Telescope (VLT) of the European Southern Observatory and to allow new science. It is thus important to develop the VLT array concept bearing in mind the need to obtain the highest stability, while

Cabral, Alexandre et al.

Advertised on: