No CrossRef data available.
Published online by Cambridge University Press: 30 March 2016
A description of the instrument is given. It is expected to obtain positions, annual proper motions and parallaxes for 100 000 stars in a 2.5 years mission. The accuracy (s.e.) will be for stars of mB < 11 and about at mB=14. An extension of the mission to 3.5 years would improve the annual proper motion to for stars brighter than mB = 9.