منابع مشابه
Small Field Ccd Astrometry with a Long Focus Reflector Telescope
We discuss the use of the block adjustment method for determining astrometric positions from a mosaic of CCD frames taken with a long focus reflector telescope. The observations cover an area of 25 × 25 around the open cluster Rup21. The source of reference positions was the Tycho-2 Catalogue. The internal error in the measured positions is analyzed, and the external error is estimated from com...
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Sets of short exposure, guided CCD frames are used to measure the noise added by the atmosphere to differential astrometric observations. Large nightly variations that are correlated with the seeing have been found in the data obtained over 2 years at the KPNO and CTIO 0.9–meter telescopes. The rms noise added by the atmosphere, after a linear transformation of the raw x, y data, is found to be...
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Orbital solutions for binary or multiple stellar systems that combine astrometry (e.g., position angles and angular separations) with spectroscopy (radial velocities) have important advantages over astrometric-only or spectroscopic-only solutions. In many cases they allow the determination of the absolute masses of the components, as well as the distance. Yet, these kinds of combined solutions ...
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Searching for extrasolar planets by direct detection is extremely challenging for current instrumentation. Indirect methods, that measure the effect of a planet on its host star, are much more promising and have indeed led to the discovery of nearly all extrasolar systems known today. While the most successful method thus far is the radial velocity technique, new interferometric instruments lik...
متن کاملPrinciples of statistical astrometry
We present a coherent scheme of ‘statistical astrometry’ for high-precision measurements. Statistical astrometry provides methods and tools for treating quantitatively the overall statistical effect of the presence of many individually unresolved or unmodelled astrometric binaries in a stellar ensemble. The non-linear motions of the photo-centers of these binaries give rise to deviations from l...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1995
ISSN: 0074-1809
DOI: 10.1017/s0074180900227745