For the past 16 years, the Visible Multi-Object Spectrograph attached to the European Southern Observatory’s Very Large Telescope captured the spectra of tens of thousands of galaxies, helping astronomers learn more about how massive galaxies form, grow and evolve. Before the venerable instrument was decommissioned 24 March, VIMOS captured this stunning view of Arp 271, showing two gravitationally interacting galaxies 110 million light years away.
VIMOS was designed to study large numbers of targets at the same time. First, the instrument captured an image of a group of galaxies, for example. Astronomers then would identify targets of interest in the image and a laser would cut precise slits in a metal plate that would allow the light from just those galaxies to pass through. After the plate was inserted in VIMOS, the instrument could collect the spectra of all the target galaxies at the same time.