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Absolute proper motions of open clusters. I. Observational data
Mean proper motions and parallaxes of 205 open clusters were determinedfrom their member stars found in the Hipparcos Catalogue. 360 clusterswere searched for possible members, excluding nearby clusters withdistances D < 200 pc. Members were selected using ground basedinformation (photometry, radial velocity, proper motion, distance fromthe cluster centre) and information provided by Hipparcos (propermotion, parallax). Altogether 630 certain and 100 possible members werefound. A comparison of the Hipparcos parallaxes with photometricdistances of open clusters shows good agreement. The Hipparcos dataconfirm or reject the membership of several Cepheids in the studiedclusters. Tables 1 and 2 are only available in electronic form at theCDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or viahttp://cdsweb.u-strasbg.fr/Abstract.html
| The Henry Draper Extension Charts: A catalogue of accurate positions, proper motions, magnitudes and spectral types of 86933 stars
The Henry Draper Extension Charts (HDEC), published in the form offinding charts, provide spectral classification for some 87000 starsmostly between 10th and 11th magnitude. This data, being highlyvaluable, as yet was practically unusable for modern computer-basedastronomy. An earlier pilot project (Roeser et al. 1991) demonstrated apossibility to convert this into a star catalogue, using measurements ofcartesian coordinates of stars on the charts and positions of theAstrographic Catalogue (AC) for subsequent identification. We presenthere a final HDEC catalogue comprising accurate positions, propermotions, magnitudes and spectral classes for 86933 stars of the HenryDraper Extension Charts.
| The chemical composition of six southern clusters and associations
Seventy-one early-type main-sequence stars have been observedspectroscopically in five southern galactic clusters and a looseassociation. Hydrogen-line profiles and helium-diffuse-line equivalentwidths have been measured for all stars, together with line strengthsfor metal and helium nondiffuse lines in 27 stars with small projectedrotational velocities. Stromgren photometry has been obtained for starswhere previous results do not exist, and effective temperatures havebeen determined from the index. Surface gravities have been estimatedprimarily from theoretical profiles fitted to the H-delta absorptionline, and also from H-beta photometry. Abundances, deduced fromcomparison with LTE and non-LTE model-atmosphere calculations, aregenerally found to be consistent with a normal early-type stellarcomposition.
| Distance Moduli of Open Clusters.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1965ApJS...12..215H&db_key=AST
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Membro dei seguenti gruppi:
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Osservazione e dati astrometrici
| Costellazione: | Sagittario |
| Ascensione retta: | 18h04m24.32s |
| Declinazione: | -22°26'18.8" |
| Magnitudine apparente: | 9.859 |
| Moto proprio RA: | 7.9 |
| Moto proprio Dec: | 2.1 |
| B-T magnitude: | 9.992 |
| V-T magnitude: | 9.87 |
Cataloghi e designazioni:
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