4MOST: the 4-metre multi-object spectroscopic telescope project in the assembly, integration and test phase

4MOST is a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's 4m-VISTA telescope at Paranal, Chile. Its key specifications are: a large field of view of 4.4 square degrees, a high multiplex fibre positioner based on the tilting spine principle that positions 2436 science fibres in the focal surface of which 1624 fibres go to two low-resolution optical spectrographs (R = lambda/Delta lambda similar to 6500) and 812 fibres transfer light to the high-resolution optical spectrograph (R similar to 20,000). Currently, almost all subsystems are completed and full testing in Europe will be finished in spring 2023, after which 4MOST will be shipped to Chile. An overview is given of instrument construction and capabilities, the planned science of the consortium and the recently selected community programmes, and the unique operational scheme of 4MOST.

Automated summary

4MOST is a new high-multiplex, wide-field spectroscopic survey facility being constructed for ESO's 4m-VISTA telescope in Chile. It has a large field of view and a high multiplex fibre positioner, enabling both high-resolution and low-resolution optical spectroscopy.