Phase Referencing and Narrow-Angle Astrometry in Current and Future Interferometers
arXiv:astro-ph/0407280 · doi:10.1117/12.549440
Abstract
Atmospheric turbulence is a serious problem for ground-based interferometers. It places tight limits on both sensitivity and measurement precision. Phase referencing is a method to overcome these limitations via the use of a bright reference star. The Palomar Testbed Interferometer was designed to use phase referencing and so can provide a pair of phase-stabilized starlight beams to a second (science) beam combiner. We have used this capability for several interesting studies, including very narrow angle astrometry. For close (1-arcsecond) pairs of stars we are able to achieve a differential astrometric precision in the range 20-30 micro-arcseconds.
9 Pages, 7 figures. To appear in SPIE conference proceedings volume 5491, "New Frontiers in Stellar Interferometery"