ESPRESSO: the spectrograph saw its first light at the Very Large Telescope of ESO

The big moment has come: ESPRESSO, the Echelle Spectrograph for Rocky Exoplanet and Stable Spectroscopic Observations, the terrestrial planets hunters, the instrument that can unveil the secrets of a new Physics, registered the first light of celestial objects on the 8.2m VLT telescope of ESO.

On the night of 27 November 2017, ESPRESSO finally collected the light of some stars and quasars through VLT, thus showing its unprecedented capacity of radiation analysis with the first obtained “spectra”. These first results have proved the expected high performance of the instrument.

ESPRESSO had been dismounted and sent to Chile this past August (for the news see here), to where it got after a perilous and long voyage. The boxes found themselves in transit to Miami between both Irma and Maria hurricanes and only arrived at Paranal Observatory in September, after tossing around and around; but they made it at last.

All components underwent integrity tests in record time, and the instrument was mounted again aligned and tested in the underground of the Coudé Combined Laboratory. Here it benefits from those particularly stable conditions – mechanical as well as temperature and pressure conditions - necessary to obtain absolute precision. All subsystems have come back to life: electronics, optomechanics , detectors, front end, calibrations, control, optical fibres, lenses, mirrors, diffraction grating, computers, programmes… and after few tests they all started to perform their roles.

In this way ESPRESSO has been able to show its perfect shape from the very beginning. An instrument whose quality is by no means superior to that of the instrument which, up to now, had been considered as the most accurate instrument for the detection of terrestrial planets from the ground , HARPS.

The ESPRESSO team of Trieste Observatory is composed by Stefano Cristiani, Co-PI of the instrument, Paolo Molaro, Project Scientist, Paolo Di Marcantonio, Software system engineer and responsible for the control software, Roberto Cirami, control software, Giorgio Calderone, control software, Paolo Santin, control software, Igor Coretti, responsible for the electronics group, Veronica Baldini, electronics, Valentina D’Odorico, responsible for the data analysis software group and Guido Cupani, data analysis software.

As everybody would expect, the first comments of the project staff now hosted in Chile are enthusiastics.

Giorgio Calderone “feels like a musician playing in an orchestra, who has long prepared for playing the right note at the right time so as to perform a terrific concert. I have practiced and rehearsed for 3 years in order to have all ESPRESSO components play in unison the same air, on top of Cerro Paranal, one hour after the sunset of 27 November”.

And very thrilled is Guido Cupani “despite all the years I have spent working on devise and obtain the various subsystems of the instrument, when I saw the spectra appearing on the screen it seemed almost a miracle… It is incredible to think that the light we see has crossed the Universe to get to us. Yet, that is what happened, and the very sophisticated system of optical elements just did its job in dispersing this light in wavelengths so as to reveal its inestimable content of information. The thrill, in this case, was twofold because after few minutes we had already got the calibrated spectrum on which to make first scientific measurements”.

Guido continues: “ I’m fascinated by the idea that ESPRESSO can cast a new light on some fundamental questions: how common are terrestrial planets? Physical constants are really constant or do they change with time? Still, that is not all. It is as if our view of the cosmos had become more vivid all of a sudden: using all four telescopes of VLT simultaneously we will trace a much more accurate map of the intergalactic medium , and so clarify many important open questions on its evolution as related to galaxies evolution. As it is often the case, I think that what we will find out will impress us. The ESPRESSO adventure has just started!”.

Last, Paolo Di Marcantonio adds:” ESPRESSO represents a watershed for ESO instrumentation. It is one of the very first instruments on which the old control technology based on VME buses has entirely been replaced by new controls based on PLC and on technical high performance cameras. The validity/soundness of these choices was evident throughout all project phases and is supported by the fact that this technology will also be adopted for future ELT instrumentation. Adding that this required an ex-novo development of various parts of both control and data analysis software, it was really an honour for me to have the opportunity of coordinating a competent and tight-knit team capable to successfully face such a thrilling challenge.

More information and images are available on MEDIA INAF news.



The OATs components of: the ESPRESSO Team

 

Other Images from Cile: