The aim of the Vista Hemisphere Survey (VHS) is to carry out a near Infra-Red survey, which when combined with other VISTA Public Surveys will result in coverage of the whole southern celestial hemisphere (20,000 square degrees) to a depth 30 times fainter than 2MASS/DENIS in at least two wavebands (J and K), with an exposure time of 60 seconds per waveband to produce median 5spoint source (Vega) limits of J = 20.2 and K = 18.1. In the South Galactic Cap, ~5000 square degrees will be imaged deeper with an exposure time of 120 seconds and also including the H band producing median 5sigmna point limits of: J = 20.6; H = 19.8; K = 18.5. In this 5000deg² region of sky deep multi-band optical (grizY) imaging data will be provided by the Dark Energy Survey (DES). The remainder of the high galactic latitude (|b|>30°) sky will be imaged in YJHK for 60sec per band to be combined with ugriz waveband observations from the VST ATLAS survey.

The medium term scientific goals of VHS include:

• the discovery of the lowest-mass and nearest stars
• deciphering the merger history our own Galaxy via stellar galactic structure
• measurement of large-scale structure of the Universe out to z~1 and measuring the properties of Dark Energy
• discovery of the first quasars with z>7 for studies of the baryons in the intergalactic medium during the epoch of reionization

In addition the VHS survey will provide essential multi-wavelength support for the ESA Cornerstone missions; XMM-Newton, Planck, Herschel and GAIA.