MOONS records its “First Light” with significant involvement from Ciências ULisboa

MOONS, the new spectrograph installed at the Very Large Telescope (VLT) in Chile, has recorded its ‘First Light’. This moment marks the start of observations by an instrument that has benefited from significant Portuguese scientific and technological contributions. Researchers and staff from the Institute of Astrophysics and Space Sciences (IA) and Ciências ULisboa were involved in the development of key components of MOONS.

Installed at an altitude of over 2,600 metres, the new astronomical instrument uses 1,000 robotically controlled optical fibres. These fibres are able to position themselves autonomously, with micrometre-level precision, enabling the simultaneous observation of around 1,000 astronomical targets.

One of MOONS’s key features is its sensitivity to near-infrared light. This capability allows it to observe through the cosmic dust that often obscures the centre of the Milky Way. But that is not all: MOONS ‘opens the door’ to the possibility of studying very distant galaxies and observing the light from millions of stars.

“This first light is a remarkable achievement for astronomical instrumentation worldwide and undoubtedly represents a historic moment for astronomical instrumentation in Portugal,” says Alexandre Cabral, a researcher at the IA and the Faculty of Sciences at the University of Lisbon. For the researcher, this moment also represents “the culmination of 16 years of work, from the first conceptual sketches of the instrument to its first light”.

Meanwhile, José Afonso, a researcher at the IA and at Ciências ULisboa and co-principal investigator of MOONS, highlights the scientific scope of the equipment: “MOONS will enable us to obtain high-quality spectra for millions of galaxies spanning virtually the entire history of the Universe — from the nearest galaxies, including our own Milky Way, to the very first ones that formed, a few hundred million years after the Big Bang.”

The researcher also considers MOONS to be “a clear reflection of the maturity and consolidation of national capabilities in the study of the universe”.

With this new instrument, the team hopes to gain a better understanding of what led to the peak of galactic activity some 10 billion years ago, and what caused its more recent decline. Over its planned ten-year operational period, the spectrograph is expected to collect data on around ten million astronomical objects, which will be crucial in complementing information from missions such as ESA’s Gaia, the Vera C. Rubin Observatory and future surveys of the Universe.