University of Cambridge: New telescope opens a window to the southern sky

A powerful new telescope has captured its first glimpse of the cosmos, and could transform our understanding of how stars, galaxies and black holes evolve.

The 4MOST (4-metre Multi-Object Spectroscopic Telescope ), mounted on the European Southern Observatory's VISTA telescope in Chile, achieved its 'first light' on 18 October 2025: a milestone marking the start of its scientific mission.

Unlike a typical telescope that takes pictures of the sky, 4MOST records spectra – the detailed colours of light from celestial objects – revealing their temperature, motion and chemical makeup. Using 2,436 optical fibres, each thinner than a human hair, the telescope can study thousands of stars and galaxies at once, splitting their light into 18,000 distinct colour components.

"This is an outstanding feat made possible by an amazing development team," said Dr Roelof de Jong, Principal Investigator of 4MOST at the Leibniz Institute for Astrophysics Potsdam (AIP), which leads the international project. "The first data already look fantastic. To catch light that's travelled for billions of years in a fibre the size of a hair is mind-boggling."

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