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 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 http://ad.usno.navy.mil/ad/ucac/ .
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 2000AJ....120.2131Z)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
intro.txt 76 400 Introduction to the CD-ROM data
out.sam 88 100 *Sample output from the UCAC1
UCAC1/* . . Subdirectory with binary data / programs
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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.
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See also:
http://ad.usno.navy.mil/ucac/ : the UCAC Home Page
Byte-by-byte Description of file: out.sam
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Bytes Format Units Label Explanations
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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
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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"
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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.
* 19-Aug-2024: format migration (CDS)
(End) Francois Ochsenbein [CDS] 07-Jun-2001