  MOONS is a new conceptual design for a Multi-Object Optical and Near-infrared
Spectrograph for the Very Large Telescope (VLT), selected by ESO for a Phase A
study. The baseline design consists of 1000 fibers deployable over a field of
view of 500 square arcmin, the largest patrol field offered by the Nasmyth
focus at the VLT. The total wavelength coverage is 0.8um-1.8um and two
resolution modes: medium resolution and high resolution. In the medium
resolution mode (R=4,000-6,000) the entire wavelength range 0.8um-1.8um is
observed simultaneously, while the high resolution mode covers simultaneously
three selected spectral regions: one around the CaII triplet (at R=8,000) to
measure radial velocities, and two regions at R=20,000 one in the J-band and
one in the H-band, for detailed measurements of chemical abundances. The grasp
of the 8.2m Very Large Telescope (VLT) combined with the large multiplex and
wavelength coverage of MOONS - extending into the near-IR - will provide the
observational power necessary to study galaxy formation and evolution over the
entire history of the Universe, from our Milky Way, through the redshift desert
and up to the epoch of re-ionization at z>8-9. At the same time, the high
spectral resolution mode will allow astronomers to study chemical abundances of
stars in our Galaxy, in particular in the highly obscured regions of the Bulge,
and provide the necessary follow-up of the Gaia mission. Such characteristics
and versatility make MOONS the long-awaited workhorse near-IR MOS for the VLT,
which will perfectly complement optical spectroscopy performed by FLAMES and
VIMOS.
