Free Astronomy Magazine January-February 2026

49 JANUARY-FEBRUARY 2026 ASTRO PUBLISHING T his image shows ESO's VISTA tele- scope and its 4MOST instrument. [AIP/A. Saviauk] cosmic objects simultaneously, using more than 2400 thin optical fibres, each about the width of a human hair. This light is then directed to three separate spectrographs that split it into up to 18,000 colour com- ponents (in the visible light range from violet to red), giving us individ- ual spectra. Using these, astronomers can analyse the properties of the observed cosmic sources, including their chemical composition, velocity or distance. “Astronomers have been asking for a facility like 4MOST for a long time,” says Joar Brynnel, 4MOST Project Manager at the Leibniz Institute for Astrophysics Potsdam (AIP), Germany, the institute that led the instrument consortium. The number of objects it T his video shows 4MOST installed at ESO’s VISTA telescope, in Chile’s Atacama Desert, and ready for observations. The telescope was completely up- graded to receive the instrument. Here we see all modifications and installations for VISTA finished, the three spectrographs (black boxes) in place and connected with the glass fibres, and 4MOST ready for first light. [AIP/A. Saviauk] the southern skies. It is expected to capture and analyse the light of more than 25 million different ob- jects during its first five years of op- eration, to unravel our galactic his- tory, explore the mysteries of dark matter, and investigate the origins of stars, among many other science goals. This instrument is designed to capture the light of thousands of https://www.eso.org/public/unitedkingdom/videos/ann25007b/