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I/268               UCAC1 Catalogue                 (Zacharias+ 2000)

First U.S. Naval Observatory CCD Astrograph Catalog (UCAC1) Zacharias N., Urban S.E., Zacharias M.I., Hall D.M., Wycoff G.L., Rafferty T.J., Germain M.E., Holdenried E.R., Pohlman J.W., Gauss F.S., Monet D.G., Winter L. <Astron. J. 120, 2131-2147 (2000)> =2000AJ....120.2131Z
ADC_Keywords: Surveys ; Positional data ; Proper motions Description: The UCAC1 is a high density, highly accurate, astrometric catalog of over 27 million stars in the Southern Hemisphere in the magnitude range of about 8 to 16. This version is the first release of an ongoing project to observe the entire sky; for up-to-date information see the Web page at . The UCAC1 is a preliminary catalog. By avoiding all "problem cases" (see details in the "intro.txt" file) it is not complete. Positions, proper motions and errors are provided, together with approximate magnitudes in the 579-642nm range. The positional precision is about 20 mas for 9 to 14 mag and 70 mas at 16th mag. The errors of the proper motions are very heterogeneous, ranging from 1 to 35 mas/yr. The UCAC is an observational program using the U.S. Naval Observatory Twin Astrograph and a 4kx4k CCD camera, covering just over 1 square degree per frame with a scale of 0.9"/pixel. Observations started in January 1998 at Cerro Tololo Interamerican Observatory (CTIO) and are continuing. This first catalog contains data observed through 07 November 1999 at which time about 80% of the Southern Hemisphere was completed. Full sky coverage is expected by early 2003 after a re-location of the instrument to the Northern Hemisphere planned for early 2001. The UCAC1 is also available on CD-ROM from the US Naval Observatory. Direct request to with UCAC1 in the subject string. Notice: The data are freely available; however, any publication utilizing these data should make proper reference to USNO and the paper by Zacharias et al. (2000AJ....120.2131Z) File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file intro.txt 76 400 Introduction to the CD-ROM data out.sam 88 100 *Sample output from the UCAC1 UCAC1/* 0 . Subdirectory with binary data / programs
Note on out.sam: this file is just a sample output of the query programs. details about the complete binary data structure, and programs to query the catalogue, can be found in the UCAC1 subdirectory. A remote query program "finducac1" is also accessible for Unix or Linux, see
See also: : the UCAC Home Page Byte-by-byte Description of file: out.sam
Bytes Format Units Label Explanations
1- 8 I8 --- 1UCAC *[00000001,27425433] UCAC designation 10- 20 F11.7 deg RAdeg Right ascension (degrees), ICRS, at "Epoch" 21- 31 F11.7 deg DEdeg Declination (degrees), ICRS, at "Epoch" 33- 35 I3 mas e_RAdeg Mean error on RAdeg 37- 39 I3 mas e_DEdeg Mean error on DEdeg 41- 45 F5.2 mag UCmag Magnitude in UCAC system (579-642nm) 47- 48 I2 --- No Number of observations 50- 57 F8.3 yr Epoch Mean Epoch of observation (of position) 59- 66 F8.1 mas/yr pmRA Proper motion in RA(*cos(Dec)) 68- 75 F8.1 mas/yr pmDE Proper motion in Dec 77- 80 F4.1 mas/yr e_pmRA Mean error on pmRA 82- 85 F4.1 mas/yr e_pmDE Mean error on pmDE 87- 88 I2 --- Nc Number of catalogues
Note on 1UCAC: this star number is not provided in the original files. It represents the running line number over all data, and uses an 8-digit after the string "1UCAC"-------------------------------------------------------------------------------- History:
History: A compact version (in directory UCAC1/bindat) can be used directly for searches. It was generated in May 2001 from the ascii version distributed on CD-ROM.
(End) Francois Ochsenbein [CDS] 07-Jun-2001
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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