The Gaia-ESO survey astrophysical calibration
The GES is a wide field spectroscopic survey recently started with the FLAMES@VLT in Cerro Paranal. It will produce radial velocities more accurate than Gaia's for faint stars (down to V~18), and astrophysical parameters and abundances for ~100000 stars, belonging to all Galactic populations. 300 nights were assigned in 5 years (with the last year subject to approval after a detailed report). In particular, to connect with other ongoing and planned spectroscopic surveys, a detailed calibration program is planned, including well known clusters, Gaia benchmark stars, and special equatorial fields designed for wide field/multifiber spectrographs.