THE THIRD US NAVAL OBSERVATORY CCD ASTROGRAPH CATALOG (UCAC3)
- U.S. Naval Observatory, Washington, DC 20392 (United States)
- Yale University, P.O. Box 208101, New Haven, CT 06520 (United States)
- Scottish Universities Physics Alliance, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, Scotland (United Kingdom)
- Department of Science Operations, KM 121 CH 23, San Pedro de Atacama, II Region (Chile)
- U.S. Naval Observatory, 10391 W. Naval Observatory Road, Flagstaff, AZ 86001 (United States)
- The Boeing Company, 100 North Riverside, Chicago, IL 60606 (United States)
- European Southern Observatory, Avenida Panoramica No. 4461, Sector Aeroparque, La Serena (Chile)
The third US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC3, was released at the IAU General Assembly on 2009 August 10. It is the first all-sky release in this series and contains just over 100 million objects, about 95 million of them with proper motions, covering about R = 8-16 mag. Current epoch positions are obtained from the observations with the 20 cm aperture USNO Astrograph's 'red lens', equipped with a 4k x 4k CCD. Proper motions are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. For most of the faint stars in the southern hemisphere, the Yale/San Juan first epoch plates from the Southern Proper Motion (SPM) program (YSJ1) form the basis for proper motions. These data are supplemented by all-sky Schmidt plate survey astrometry and photometry obtained from the SuperCOSMOS project, as well as 2MASS near-IR photometry. Major differences of UCAC3 data as compared with UCAC2 include a completely new raw data reduction with improved control over systematic errors in positions, significantly improved photometry, slightly deeper limiting magnitude, coverage of the north pole region, greater completeness by inclusion of double stars, and weak detections. This of course leads to a catalog which is not as 'clean' as UCAC2 and problem areas are outlined for the user in this paper. The positional accuracy of stars in UCAC3 is about 15-100 mas per coordinate, depending on magnitude, while the errors in proper motions range from 1 to 10 mas yr{sup -1} depending on magnitude and observing history, with a significant improvement over UCAC2 achieved due to the re-reduced SPM data and inclusion of more astrograph plate data unavailable at the time of UCAC2.
- OSTI ID:
- 21443094
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Journal Name: Astronomical Journal (New York, N.Y. Online) Journal Issue: 6 Vol. 139; ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
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