منابع مشابه
CCD photometry of distant comets
While it is apparent that many comets are active beyond the canonical distance of 3 AU, few surveys of cometary activity have been performed in this region previously. Such a survey enables a more accurate determination of the proportion of comets that exhibit little or no outgassing at these distances. Results are presented of CCD observations of comets in the region of 3 AU ≤ Rh ≤ 6 AU obtain...
متن کاملCCD photometry and astrometry for visual double and multiple stars of the HIPPARCOS catalogue I. Presentation of the large scale project
A description is given of the activities of an international working group created with the aim of obtaining both photometric and astrometric observations of visual double and multiple stars with angular separations in the range of one to fifteen arcseconds, that formed part of the HIPPARCOS Input Catalogue. The scientific aims and realisations of this European network are given. About 50 obser...
متن کاملGlobular Cluster Ages and Strömgren CCD Photometry
Strömgren uvby CCD photometry can be used in a variety of ways to constrain the absolute and relative ages of globular clusters. The reddening corrected v−y, c1 diagram offers the means to derive ages that are completely independent of distance. Very precise differential ages for clusters of the same chemical composition may also be determined from such 2–color plots, or from measurements of th...
متن کاملBe star surveys with CCD photometry . II . NGC 1818 and its neighbouring cluster in the LMC ⋆
As part of an ongoing photometric survey of young Magellanic Cloud clusters we identified Be stars in NGC 1818 and a nearby smaller cluster in the Large Magellanic Cloud. The neighbouring cluster does not appear to contain any evolved stars, and its sparsely populated main sequence does not extend to stars as massive as in NGC 1818. Both clusters are younger than the surrounding field populatio...
متن کاملA Technique for Ultrahigh-Precision CCD Photometry
We present techniques for wide-field ultrahigh-precision time-sampled CCD photometry. Representing a survey of field stars, our data consist of UBVRI photometry and a V-band time series of exposures on 5 consecutive nights covering 11,500 stars in a ∼1 deg field. The resulting light curves reach precisions of 0.0020 mag per exposure in the brightest stars ( ). Light curves binned and averaged o...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1992
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/259.3.563