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3.4

CCD meridian observations at Valinhos Observatory

 

Ramachrisna Teixeira, Paulo Benevides-Soares, Tania P. Dominici, Wilson Monteiro, Sao Paulo, Michel Rapaport, J. François Le Campion, Yves Réquième, Bordeaux

 

Complete text (abstract only):

Since 1996 we have been regularly observing with a CCD micrometer transit circle at the Abrahno de Moraes Observatory in Valinhos, Brazil. The new detector system is the result of a successful cooperation with the Bordeaux Observatory. Differential astrometric and photometric observations of more than ten thousand stars per clear night, down to V = 16 mag, become feasible, making possible the current development of many observational projects:

  • Extension of the Hipparcos and Tycho catalogs to fainter objects,
  • Observation of extragalactic objects for linking the radio and optical reference frames and photometric detection of variability,
  • Low absorption windows around the galactic center direction for detecting and classifying stellar variability,
  • Solar system objects (Pluto, Neptune, Uranus, a few asteroides and major planets satellites) for dynamic research purposes,
  • Proper motion of open clusters and young stars to establish the possible connection between star formation and trajectorys of molecular clouds across the galactic disk.

Here, we presented the light curve of the source 2005-489 (BL Lac) observed in 1997, that shows variability, as well as the differences between the CCD and radio positions for 14 bright extragalactic objects (ICRF). We present too the comparison between our Pluto positions and the ephemeris DE403 and DE405 for 1996 and 1997. The mean differences (CCD DE405) obtained were:

1996 1997
Righ Ascension -0.05 ± 0.06 arcsec -0.01 ± 0.03 arcsec
Declination +0.01 ± 0.03 arcsec -0.06 ± 0.04 arcsec

Bibliographical details:

Ramachrisna Teixeira, Paulo Benevides-Soares, Tania P. Dominici, Wilson Monteiro, Michel Rapaport, J. François Le Campion, Yves Réquième: CCD meridian observations at Valinhos Observatory. In: Peter Brosche, Wolfgang R. Dick, Oliver Schwarz, Roland Wielen (Eds.): The Message of the Angles - Astrometry from 1798 to 1998. Proceedings of the International Spring Meeting of the Astronomische Gesellschaft, Gotha, May 11-15, 1998. (Acta Historica Astronomiae ; 3). Thun ; Frankfurt am Main : Deutsch, 1998, p. 190.