I/243 The PMM USNO-A1.0 Catalogue (Monet 1997)
A Catalog of Astrometric Standards
Monet D.,
Canzian B., Harris H., Reid N., Rhodes A., Sell S.
ADC_Keywords: Surveys ; Photographic catalog ; Photometry, photographic ;
Abstract:
USNO-A1.0 is a catalog of 488,006,860 sources whose positions can be
used for astrometric references. These sources were detected by the
Precision Measuring Machine (PMM) built and operated by the U. S.
Naval Observatory Flagstaff Station during the scanning and processing
of the Palomar Observatory Sky Survey I (POSS-I) O and E plates, the
UK Science Research Council SRC-J survey plates, and the European
Southern Observatory ESO-R survey plates. The PMM detects and
processes at and beyond the nominal limiting magnitude of these
surveys, but the large number of spurious detections requires that a
filter be used to eliminate as many as possible. USNO-A's sole
inclusion requirement was that there be spatially coincident
detections (within a 2 arcsecond radius aperture) on the blue and red
survey plate. For field centers of -30 degrees and above, data come
from POSS-I plates, while data from field centers of -35 and below
come from SRC-J and ESO-R plates.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
out.sam 58 1000 *Sample output (out of 526,280,881 stars)
read.me 79 260 Author's Original Top-Level Description
read.ast 78 144 Discussion of astrometry in USNO-A1.0
read.pht 78 187 Discussion of photometry in USNO-A1.0
read.pmm 79 516 Overview of Precision Measuring Machine
usnoa/* . . Compact version of Catalogue (3.4Gbytes)
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Note on out.sam: this file is actually the result of the execution
of the query on the compacted version of USNO-A1.0 at CDS
(in subdirectory usnoa, not yet accessible)
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See also:
I/220 : The HST Guide Star Catalog, version 1.1 (Lasker+ 1992)
I/252 : The USNO-A2.0 Catalogue (supersedes this version)
http://www.usno.navy.mil/pmm/ : The Precision Measuring Machine
home page at Flagstaff Station, U.S. Naval Observatory
Byte-by-byte Description of file: out.sam
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Bytes Format Units Label Explanations
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1- 13 A13 --- USNO-A1.0 *Original designation in USNO-A1.0 catalogue
15- 24 F10.6 deg RAdeg Right ascension (ICRS) mean of blue/red plates
26- 35 F10.6 deg DEdeg Declination (ICRS) mean of blue/red plates
37- 37 A1 --- GSCflag [G] 'G' when star belongs to GSC (Cat. I/220)
39- 39 A1 --- Mflag [*] '*' magnitudes are probably wrong
41- 44 F4.1 mag Bmag Magnitude from blue plate
46- 49 F4.1 mag Rmag Magnitude from red plate
51- 58 F8.3 yr Epoch *?=0.0 Mean epoch of position
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Note on USNO-A1.0:
This number allows to retrieve the exact original record: it is made
of a zone number (4 digits from 0000 to 1725 representing the distance
in 0.1deg to the South Pole, stepped by 75 = 7.5degrees), and a number
in the area (8 digits, order by IRCS (J2000) RA);
****Note that this number differs from the USNO-A2.0 one.
Note on Epoch:
Epoch is the averaged date of observation between the blue and
the red plates.
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History:
* 03-Nov-1998: This catalog is superseded (from October 1998) by
USNO-A2.0, Cat. I/252
* 26-Aug-2024: format migration (CDS)
Author's Address:
Dave Monet
US Naval Observatory Flagstaff Station
PO Box 1149 (US Mail Only)
West Highway 66 (FedEx, UPS, etc.)
Flagstaff AZ 86001 USA
Voice: 520-779-5132
FAX: 520-774-3626
e-mail:
(End) Francois Ochsenbein [CDS] 18-Jul-1998