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Extension of The Optical Reference Frame: Ground Based

Published online by Cambridge University Press:  14 August 2015

N. Zacharias
N. Zacharias*
Affiliation:
U.S. Naval Observatory, nz@pyxis.usno.navy.mil 3450 Mass.Av.NW, Washington DC 20392, USA

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The International Celestial Reference Frame (ICRF) is realized by the positions of 608 compact extragalactic radio sources (Ma & Feissel 1997) with milliarcsecond (mas) and sub-mas accuracy, all being on the same system, the International Celestial Reference System (ICRS). The Hipparcos Catalogue (ESA 1997) is the practical realization of the ICRF at optical wavelengths, giving accurate positions (≈ 1 mas) at the mean epoch of 1991.25 and proper motions (≈ 1 mas/yr) for 117995 stars. This is about 2.5 stars per square degree, most being in the 7 to 9 magnitude range and a few as faint as 12. However, for many astronomical applications the Hipparcos Catalogue is not dense enough and does not reach faint enough magnitudes.

The Tycho Catalogue (ESA 1997) provides accurate positions (≈ 25 mas) for about one million stars to magnitude 11, but lacks precise proper motions. Ground-based observations are an efficient way to complement the Hipparcos mission and to extend the optical reference frame to fainter magnitudes and yield a denser grid of astrometric standard stars. New reductions of early epoch photographic data will be used to provide highly accurate proper motions for stars to about magnitude 12. Current and new observational projects will extend the optical reference frame to even fainter magnitudes.

Type
II. Joint Discussions
Information
Highlights of Astronomy , Volume 11 , Issue 1: Highlights of Astronomy. As presented at the XXIIIrd General Assembly of the IAU (Part A), 1997 , 1998 , pp. 300 - 303
Copyright
Copyright © Kluwer 1998

References

Carlsberg Meridian Catalogue La Palma Number 9 (1997)Google Scholar
de Vegt, C. (1988) in Mapping the Sky, IAU Sympos.133, Eds. Debarbat, S., Eddy, J.A., Eichhorn, H.K. & Upgren, A.R., Kluwer Acad. Publ., Dordrecht, p. 211 Google Scholar
Eichhorn, H. (1974) Astronomy of Star Positions. Fred. Ungar Publ. Co., New York Google Scholar
ESA (1997) The Hipparcos and Tycho Catalogues. European Space Agency, SP-1200Google Scholar
Gauss, F.S., Zacharias, N., Rafferty, T.J., Germain, M.E., Holdenried, E.R., Pohlman, J.W. & Zacharias, M.I. (1997) A new astrometric survey of the southern hemisphere, BAAS 28, No. 4, 1282 Google Scholar
Girard, T.M., Platais, I., Kozhurina-Platais, V., van Aliena, W.F., & Lopez, C.E. (1997) The Southern Proper Motion Program I, submitted to AJGoogle Scholar
Klemola, A.R., Jones, B.F., & Hanson, R.B. (1987) AJ 94, 501 Google Scholar
Klemola, A.R., Jones, B.F., & Hanson, R.B. (1993) National Space Science Data Center/ADC Catalog No.A1199Google Scholar
Lasker, B.M. (1993) Photographic Surveys and their Digitization, in Workshop on Databases for Galactic Structure, eds. Philip, A.G.D., Hauck, B., & Upgren, A.R., L. Davis Press, Schenectady, NY p. 77 Google Scholar
Ma, C. & Feissel, M. (1997) Definition and Realization of the International Celestial Reference System by VLBI Astrometry of Extragalactic Objects, IERS Technical Note 23 Google Scholar
Monet, D. 1996, The ALO and SALO catalogs on CD-ROM, U.S. Naval ObservatoryGoogle Scholar
Murray, C.A. & Corben, P.M. (1979) MNRAS 187, 723 Google Scholar
Richmod, M. (1993) The Sloan Digital Sky Survey, in Workshop on Databases for Galactic Structure, eds. Philip, A.G.D., Hauck, B., & Upgren, A.R., L. Davis Press, Schenectady, NY, p. 207 Google Scholar
Röser, S, Morrison, J., Bucciarelli, B., Lasker, B. & McLean, B. (1997) Contents, test results, and data availability for GSC 1.2, in proceedings IAU Symposium No.179, Baltimore, USA, in pressGoogle Scholar
Stone, R.C., Monet, D.G., Monet, A.K.B., Walker, R.L., Abies, H.D., Bird, A.R., & Harris, F.H. (1996) AJ, 111, 1721 Google Scholar
Urban, S.E., Corbin, T.E., Wycoff, G.L., Martin, J.C., Jackson, E.S., Zacharias, M.I., & Hall, D.M. (1998) The AC 2000: The astrographic Catalogue on the System Defined by the Hipparcos Catalogue, in preparation Google Scholar
Zacharias, N., de Vegt, C., Winter, L., & Weneit, W. (1994) Some results of CCD-camera based astrometric plate measurements, Proceedings of the IAU Sympos. 161, p. 285 Eds.: MacGillivray, et al., Kluwer, Dordrecht Google Scholar
Zacharias, N. (1997) Astrometric Quality of the USNO CCD Astrograph (UCA), AJ, 113, 1925 Google Scholar