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Session 16 - Astrometry.
Display session, Wednesday, January 07
SIM, the Space Interferometry Mission, will perform very accurate astrometric measurements on objects as faint as 20th magnitude using a 10 m baseline optical interferometer. SIM is designed to perform narrow-angle, wide-angle and global astrometry, the latter by means of an astrometric grid, serving as a reference frame covering the whole celestial sphere. Sensitivities of SIM astrometric performance and grid accuracy vs. instrumental parameters and sky coverage schemes will be presented. Assuming the astrometric grid of bright stars is known to the desired precision, we then estimate the accuracy by which the astrometric parameters of single objects could be derived. This allowed us to test extensively our data reduction model with respect to its parameters, including the observing scenario, the number of grid stars necessary per science target star and the field of regard of the instrument. We will discuss the problems of finding suitable astrometric grid objects and thus the consequences of astrometric jitter due to undetected companions of grid or science stars.
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Program listing for Wednesday