Microarcsecond Astrometric Interferometry

Obervational Model for Microarcsecond Astrometry with the Space Interferometry Mission

The Space Interferometry Mission (SIM) is a space-based long-baseline optical interferometer for precision astrometry. One of the primary objectives of the SIM instrument is to accurately determine the directions to a grid of stars, together with their proper motions and parallaxes, improving a priori knowledge by nearly three orders of magnitude. The basic astrometric observable of the instrum...

Astrometric optical interferometry with non-evacuated delay lines

The effects of longitudinal dispersion in long baseline optical interferometry with non-evacuated delay lines are analyzed. A new technique is proposed for group delay tracking, with phase measurements in two wavebands only. Sensitivity and instrumental uncertainties are further investigated, together with the dependence on stellar color temperature. To a precision level of a few 10−10 rad, lim...

Astrometric surveys

Astrometric surveys are a basic tool for galactic astronomy: they provide the only distance determination without assumption about the observed object as well as two components of the space velocity. A large number of stars, observed in a systematic way, yield to an unbiased sampling of the Galaxy and, for the most accurate surveys, of the brightest parts of Local Group galaxies, at larger and ...

Some aspects of Relativistic Astrometry from within the Solar System

In this article we outline the structure of a general relativistic astrometric model which has been developed to deduce the position and proper motion of stars from 1-microarcsecond optical observations made by an astrometric satellite orbiting around the Sun. The basic assumption of our model is that the Solar System is the only source of gravity, hence we show how we modeled the satellite obs...

MAXIM MicroArcsecond X-ray Imaging Mission