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Improvement of Hipparcos Proper Motions in Declination
More than a decade elapsed after the HIPPARCOS ESA mission (ESA 1997)observations have been collected. This first astronomical satellitemission was less than 4 years long so that 1991.25 is the epoch of theHIPPARCOS Catalogue. Many other projects have checked or improvedHIPPARCOS data. Also, a long series of ground - based opticalobservations of some stars included in HIPPARCOS Catalogue, made withPhotographic Zenith Tubes (PZT) are useful for the task of improving theproper motions of these stars. The ARIHIP Catalogue (after ACT, TYCHO -2, FK6, GC+HIP, TYC2+HIP) is a combination of the HIPPARCOS and someground - based data, and the ARIHIP proper motions are more accuratethan the HIPPARCOS ones. Here we present a new step of our procedure ofcalculation; between PZT data we added the HIPPARCOS position withsuitable weight - the point with the coordinates (1991.25, 0ŭ0)in our case. The method was applied to 202 stars observed at RichmondPZTs in the course of a few decades. The result is better proper motionsin declination for these HIPPARCOS stars, and a good agreement withARIHIP proper motions (we found 128 common Richmond and ARIHIP stars tocheck our result). Also, we present the result for other 74 Richmondstars which are not found in ARIHIP.
| Distance to the anti-center shell
High-resolution, high-sensitivity echelle spectra have been obtainedtowards early-type stars located within the boundaries of theAnti-Center Shell (ACS), an anomalous velocity H I structure in theanticenter region of the Galaxy. The observations indicate that theshell is certainly more distant than 500 pc, and quite possibly moredistant than 2500 pc. No anomalous velocity C II absorption featureswere detected. These results support the hypothesis that the ACS is theresult of collision of high-velocity clouds with the Galactic H I disk.
| Photoelectric measurements of lunar occultation. VI. Further observational results.
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1973AJ.....78..482D&db_key=AST
| UBV Photometry of 173 PZT Stars
Abstract image available at:http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1971PASP...83..177W&db_key=AST
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| Takýmyýldýz: | Ikizler |
| Sað Açýklýk: | 06h28m45.03s |
| Yükselim: | +25°37'15.3" |
| Görünürdeki Parlaklýk: | 8.528 |
| Uzaklýk: | 3125 parsek |
| özdevim Sað Açýklýk: | 0.1 |
| özdevim Yükselim: | -1.8 |
| B-T magnitude: | 8.551 |
| V-T magnitude: | 8.53 |
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