PRIMA, the instrument for Phase Referenced
Imaging and Micro-arcsecond Astrometry, will implement the dual-feed
capability at the ESO Very Large Telescope
ESPRI will use PRIMA
to combine the K-band light from two 1.8m diameter Auxiliary Telescopes
(ATs) and interferometrically measure with very high accuracy the angular
separation between two stars (astrometry). One of the two stars will
typically be a distant background star (the reference star), the other one
a nearby target star. From the relative motion of the two stars we will
deduce the existence and orbital parameters of planets around the target
In order to reach this goal, a consortium lead by the Observatoire de
Geneve (Switzerland), the Max Planck Institute for Astronomy, and the
Landessternwarte Heidelberg, has built the Differential Delay
Lines for PRIMA and develops the astrometric data reduction software and
all necessary astrometric operation tools. The PRIMA facility is still
under commissioning by ESO and is planned
to become fully operational in 2014.
MPIA is involved with the science
program, the development of the Differential Delay Line (DDL) hardware, the
error budget, the
development of the strategy and planning of
observations and the data reduction software.
The ESPRI project has been terminated in 2014 because ESO has canceled the
PRIMA project and thus the PRIMA facility will not be available for ground-based astrometry.
The ESPRI consortium will use the guaranteed observing time granted for it's contributions
to PRIMA to carry out an alternative exoplanet search program via direct imaging with NaCo.
The new project web page can be found