4MOST Data Services

This is the global entry point to the 4MOST data, offering static data releases with the focus on enabling science using the 4MOST data products.

The 4MOST consortium has been selected by the European Southern Observatory (ESO) to provide the ESO community with a fibre-fed spectroscopic survey facility on the VISTA telescope with a large enough field of view to survey a large fraction of the southern sky within a few years.

4MOST will simultaneously obtain spectra of roughly 2400 objects distributed over an hexagonal field of view of 4.2 square degrees. The large amount of multiplexing in 4MOST, combined with its high spectral resolution, enables the detection of chemical and kinematic substructures in the stellar halo, bulge and thin and thick discs of the Milky Way, thus helping to unravel the origin of our home galaxy.

The instrument will also have enough wavelength coverage to secure velocities of extra-galactic objects in a large redshift range, thus enabling measurements of the evolution of galaxies, black holes, and the structure of the cosmos.

4MOST is currently in its Manufacturing, Assembly, Integration and Test Phase with an expected start of full science operations in the first quarter of 2026.

Image credits: AIP/Allar Saviauk, VISTA Telescope: ESO/The VISTA Survey, Galaxies and nebula: NASA, ESA and the Hubble SM4 ERO Team