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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.
| Polarimetric investigation of background stars in the region of T and RY Tau Electropolarimetric observations of 97 background stars in the TTauri/RY Tauri region, obtained with the 40-cm Cassegrain telescope ofthe Biurakan Astrophysical Observatory in December 1982, are reportedand interpreted in terms of local-magnetic-field effects oncometary-nebula bending. The data are presented in a table, and thedependence of polarization position angle on declination is establishedin a graph and attributed to a continuous variation in the direction ofthe magnetic field. From the magnitude of the effect, however, it isconcluded that the observed bending of the cometary nebulae in theregion results from the combined influence of the local magnetic momentand the magnetic moment of the star itself (as proposed by Vardanian,1983) rather than from the local moment alone.
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Pozíciós és asztrometriai adatok
Csillagkép: | Bika |
Rektaszcenzió: | 04h23m45.82s |
Deklináció: | +21°23'46.0" |
Vizuális fényesség: | 9.492 |
RA sajátmozgás: | 5.6 |
Dec sajátmozgás: | -5.5 |
B-T magnitude: | 11.126 |
V-T magnitude: | 9.627 |
Katalógusok és elnevezések:
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