A quick-look reduction of DIVA's observations of Hipparcos stars will contribute to the selection of the candidates for the SIM astrometric grid. In the last two years the feasibility of DIVA has been demonstrated in a study with industry, and a careful assessment of the astronomical performance has been carried out. Position angles and separations of 83 visual binaries have been measured with a photoelectric phase-grating interferometer on a 1-m reflector. Major scientific targets of DIVA are: cosmic distance scale, galactic kinematics, stellar physics, faint objects in the solar neighbourhood and binaries. DIVA (Double Interferometer for Visual Astrometry) is a small satellite planned for launch in 2003. After a few years, repeated observations of the grid allow one to determine the orientation of the interferometer baseline. A minimum mission length of 24 months is foreseen. The Section publishes these Circulars which contain measures of visual double stars using micrometers, CCD cameras and on-line astrometry as well as a. As a result of a recently performed feasibility study DIVA is technologically ready for a launch in 2003. ![]() The six mirrors, or siderostats, are mounted at regular intervals along a Y-shaped. The typical accuracy for a star with V = 9 and B-V = 0.9 will be 0.2 mas for the parallaxes, 0.15 mas for positions and 0.25 mas/y for proper motions. The interferometer here takes a page from its radio-astronomy counterpart, the Very Large Array in Socorro, N.M. Patrick Moores Practical Astronomy Series Observing and Measuring Visual Double Stars Volume 64 More than One Sun Argyle, R. Multicolour photometry will be obtained down to V = 13. DIVA will measure the parallaxes, the positions, the motions and the brightness of some 40 million stars. ![]() 1.338 pc distant is in fact a visual binary with the two stars labelled Cen A. DIVA - A Space-Borne Fizeau Interferometer for Global Astrometry and Photometryġ94, Working on the Fringe: Optical and IR Interferometry from Ground and SpaceĭIVA (Double Interferometer for Visual Astrometry) is a Fizeau interferometer on a small satellite which is to perform a complete sky survey down to about V = 15. Visual binaries Spectroscopic binaries Eclipsing binaries Astrometric.
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