I/297 NOMAD Catalog (Zacharias+ 2005)
Naval Observatory Merged Astrometric Dataset (NOMAD)
Zacharias N., Monet D.G., Levine S.E., Urban S.E., Gaume R., Wycoff G.L.
<San Diego AAS Meeting, January (2005)>
=2004AAS...205.4815Z 2004AAS...205.4815Z
ADC_Keywords: Positional data ; Proper motions ; Surveys ;
Photometry, photographic ; Photometry, infrared
Description:
The Naval Observatory Merged Astrometric Dataset (NOMAD) contains
astrometric and photometric data for over 1 billion stars derived from
the Hipparcos (I/239), Tycho-2 (I/259), UCAC2 (I/289), and USNO-B1.0
(I/284) catalogs for astrometry and optical photometry, supplemented
by 2MASS (II/246) near-infrared photometry. For each unique star the
"best" astrometric and photometric data are chosen from the source
catalogs and merged into a single dataset. A sequence of priorities is
followed and NOMAD contains flags to identify the source catalogs and
gives cross-reference identifications. This first release of NOMAD is
not a compiled catalog; that is, if a star is identified in more than
1 of the above mentioned catalogs, only 1 catalog entry is chosen.
Thus the local and global systematic errors of the various source
catalogs will be present in this version of NOMAD. All source catalogs
astrometric data are on the International Celestial Reference System
within the limitations of the source catalogs.
For more information, see
https://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/nomad
A dedicated remote query program can be downloaded from
http://cdsweb.u-strasbg.fr/doc/cdsclient.html
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
out.sam 172 1000 Example of the an output of NOMAD-1
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See also:
https://www.usno.navy.mil/USNO/astrometry/optical-IR-prod/nomad : NOMAD
Home Page
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
I/259 : The Tycho-2 Catalogue (Hog+ 2000)
I/284 : The USNO-B1.0 Catalog (Monet+ 2003)
I/289 : UCAC2 Catalogue (Zacharias+ 2004)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
Byte-by-byte Description of file:out.sam
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Bytes Format Units Label Explanations
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1- 12 A12 --- NOMAD1 NOMAD-identifier (1)
14- 24 F11.7 deg RAdeg Right ascension in J2000, Ep=J2000
26- 36 F11.7 deg DEdeg Declination in J2000, Ep=J2000
38- 49 A12 --- USNO-B1 Identifier in USNO-B1 (Cat. I/284) (1)
51- 58 I8 --- UCAC2 ? Number in UCAC2 (Cat. I/289)
60- 71 A12 --- Tycho-2 ? Identification in Tycho-2 or Hipparcos (2)
73- 73 I1 --- f_Tycho-2 ? [*] when distance NOMAD1/Tycho-2 > 1arcsec
74- 75 A2 --- YM [YM.] Existence in YB6 or 2MASS (Cat. II/246)
77- 77 A1 --- r [BCMYTH] Source of position (3)
79- 82 I4 mas e_RAdeg Mean error on RAdeg (at epRA)
84- 87 I4 mas e_DEdeg Mean error on DEdeg (at epDE)
89- 95 F7.1 mas/yr pmRA Proper motion in RA (*cos(Dec))
97-104 F8.1 mas/yr pmDE Proper motion in Declination
106-110 F5.1 mas/yr e_pmRA Mean error on pmRA
112-116 F5.1 mas/yr e_pmDE Mean error on pmDE
118-123 F6.3 mag Bmag ?Blue magnitude
125-125 A1 --- r_Bmag [BCMYTHo] Origin of Bmag (3)
127-132 F6.3 mag Vmag ?Visual magnitude
134-134 A1 --- r_Vmag [BCMYTH] Origin of Vmag (3)
136-141 F6.3 mag Rmag ?Red magnitude
143-143 A1 --- r_Rmag [BCMYTHe] Origin of Rmag (3)
145-150 F6.3 mag Jmag ?Infrared J magnitude (from 2MASS)
152-157 F6.3 mag Hmag ?Infrared H magnitude (from 2MASS)
159-164 F6.3 mag Kmag ?Infrared K magnitude (from 2MASS)
166-170 A5 --- Xflags Hexadecimal flags (4)
172-172 A1 --- R ? [R*] Recommended (R) or Problematic (*) (4)
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Note (1): NOMAD and USNO designations consist in 2 numbers
separated by a dash of the form: zone-number
where zone (0000-1799) indicates a declination strip from the South
Pole (0.1deg wide), and number is a sequential number increasing
with right ascension.
Note (2): The Tycho-2 number (Cat. I/259) is made of 3 numbers separated
by 2dashes, while Hipparcos (Cat. I/239) is a sequential number.
Note (3): Sources of the values are defined as follows:
B = USNO-B1.0 (Monet et al., Cat. I/284)
C = UCAC2 (Zacharias et al., Cat. I/289)
M = 2MASS catalog of point sources (Cutri et al., Cat. II/246)
Y = YB6 Catalog (USNO, unpublished)
T = Tycho-2 Catalog (Hog et al., 2000, Cat. I/259)
H = Hipparcos catalog (Table I/239/hip_main)
o = Palomar-I blue (O) plate (for Bmag)
e = Palomar-I red (E) plate (for Rmag)
Note (4): Flags are written in hexadecimal (symbols 0-f) with the
following meaning:
00001 = UBBIT : Fails Blaise's test for USNO-B1.0 star
00002 = TMBIT : Fails Roc's test for clean 2MASS star
00004 = YB6 : Included in YB6 catalog (Y)
00008 = 2MASS : Included in 2MASS catalog (M)
00010 = TYBIT : Astrometry comes from Tycho2 catalog (T)
00020 = XRBIT : Alternative correlations for same (RA,Dec)
00040 = ITMBIT : Alternative correlations for same 2MASS ID
00080 = IUCBIT : Alternative correlations for same UCAC-2 ID
00100 = ITYBIT : Alternative correlations for same Tycho2 ID
00200 = OMAGBIT : Blue magnitude from O (not J) plate (o)
00400 = EMAGBIT : Red magnitude from E (not F) plate (e)
00800 = TMONLY : Object found only in 2MASS catalog (M)
01000 = HIPAST : Ast from Hipparcos catalog (H)
02000 = SPIKE : USNO-B1.0 diffraction spike bit set
04000 = TYCONF : Tycho2 confusion flag set
08000 = BSCONF : Bright star has nearby faint source
10000 = BSART : Faint source is bright star artifact
20000 = USEME : Recommended astrometric standard
* = one of SPIKE|YCONF|BSCONF|BSART|XRBIT|ITMBIT|IUCBIT|ITYBIT set
R = USEME (recommended astrometric standard)
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History:
* Prepared by Dave Monet.
* 25-Sep-2024: format migration (CDS)
Acknowledgements:
It is a pleasure to thank Dave Monet who forwarded a copy of the
NOMAD catalog to CDS.
(End) Francois Ochsenbein [CDS] 09-Nov-2005