The 3 columns in color are computed by VizieR, and are not part of the original data.

Note: USNO-A2.0 contains 526,280,881 sources, and is based on a re-reduction of the Precision Measuring Machine (PMM) scans from POSS-I O and E plates (>=-18°) and SRC-J and ESO-R plates (<=-20°). USNO-A2.0 was created by Dave Monet () and collaborators at Flagstaff Station, U.S. Naval Observatory.
The major difference between USNO-A2.0 and its previous version USNO-A1.0 is that A1.0 used the Guide Star Catalog as its reference frame whereas A2.0 uses the ICRF as realized by the USNO ACT catalog (Urban et al. 1997). The VizieR search engine uses an on-line compressed version (3.6Gbytes) which was generated at CDS.

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	USNO-A2.0	RAJ2000 deg	DEJ2000 deg	ACTflag	Mflag	Bmag mag	Rmag mag	Epoch yr
1	0.517	21 42 15.90480	-25 51 26.9604	0600-43716407	325.566270	-25.857489			20.1	17.9	1984.115

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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	USNO-B1.0	RAJ2000 deg	DEJ2000 deg	e_RAJ2000 mas	e_DEJ2000 mas	Epoch yr	pmRA mas/yr	pmDE mas/yr	Ndet	B1mag mag	R1mag mag	B2mag mag	R2mag mag	Imag mag
1	0.783	21 42 15.96552	-25 51 25.9524	0641-0909154	325.566523	-25.857209	344	336	1969.0	0	0	4	20.10	18.23	20.65	20.94
2	9.602	21 42 15.89472	-25 51 36.1620	0641-0909153	325.566228	-25.860045	620	575	1971.0	0	0	2		18.63		20.87
3	9.843	21 42 16.13136	-25 51 36.0324	0641-0909156	325.567214	-25.860009	856	294	1978.6	78	-10	3		18.75		20.41	18.97
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%3cEM%3e3&%3cFONT%20COLOR=%27#CD5B45%27>%209.843&%3cFONT%20COLOR=%27#CD5B45%27>21%2042%2016.13136&%3cFONT%20COLOR=%27#CD5B45%27>-25%2051%2036.0324&0641-0909156&325.567214&-25.860009&856&294&1978.6&%20%20%20%2078&%20%20%20-10&3&%20&18.75&%20&20.41&18.97%3cBR%3e">\EndTABLESORT

Note: 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.
An efficient remote query program findnomad1 is available in the cdsclient package, for Unix/Linux platforms

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	NOMAD1	YM	RAJ2000 deg	DEJ2000 deg	r	pmRA mas/yr	e_ (...)	pmDE mas/yr	e_ (...)	Bmag mag	r_	Vmag mag	r_	Rmag mag	r_	Jmag mag	Hmag mag	Kmag mag	R
1	0.784	21 42 15.965328	-25 51 25.94988	0641-1001973	Y.	325.5665222	-25.8572083	B	0.0	0.0	0.0	0.0	18.380	Y			20.940	B
2	9.600	21 42 15.894672	-25 51 36.15984	0641-1001972	..	325.5662278	-25.8600444	B	0.0	0.0	0.0	0.0					20.870	B
3	9.841	21 42 16.131336	-25 51 36.02988	0641-1001975	..	325.5672139	-25.8600083	B	78.0	29.0	-10.0	10.0					20.410	B

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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC2.3	RAJ2000 [****ClosingBrace(s)Inserted****]
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RAJ2000

%22>%5cFONT SIZE=-1degDEJ2000
degEpoch
yrFmag
magjmag
magVmag
magNmag
magClass

a
pixe

1 0.58321 42 15.89784-25 51 26.9604SCJO018127325.566241-25.8574891983.448  20.71    3 1.36 0.34 %0a%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	RAJ2000 "h:m:s"	DEJ2000 "d:m:s"	e_RAJ2000 mas	e_DEJ2000 mas	Nr	Rmag	z	LQAC	oRA mas	oDE mas
1	0.162	21 42 15.935133	-25 51 26.71800	21 42 15.9351	-25 51 26.718	69.3	145.5	6	19.47		LQAC

%0a%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	RAJ2000 deg	DEJ2000 deg	pmRA mas/yr	pmDE mas/yr	Jmag mag	Kmag mag	b1mag mag	b2mag mag	r1mag mag	r2mag mag	imag mag	No	fl
1	0.113	21 42 15.92400	-25 51 26.4924	325.566350	-25.857359	-1.6	-19.8			20.10	20.65	18.23	20.94		4	0
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%3cEM%3e1&%3cFONT%20COLOR=%27#CD5B45%27>%200.113&%3cFONT%20COLOR=%27#CD5B45%27>21%2042%2015.92400&%3cFONT%20COLOR=%27#CD5B45%27>-25%2051%2026.4924&325.566350&-25.857359&%20%20%20%20-1.6&%20%20%20-19.8&%20&%20&20.10&20.65&18.23&20.94&%20&%204&%200%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ66386857196e4d&-out.add=.&-source=I/317/sample&PPMXL===1217672121481416218' class='full'2 9.32621 42 15.89376-25 51 35.8848325.566224-25.859968 21.0 5.3        18.6320.87   2 0 3 9.93821 42 16.08960-25 51 36.2736325.567040-25.860076 75.8 -15.3        18.7520.4118.97 3 0 %0a%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	ICRF	IVS	IERS	fl	RAJ2000 "h:m:s"	e_ s	DEJ2000 "d:m:s"	e_ arcsec	Corr	Ep d	Of d	Ol d	Nexp	Nobs
1	0.057	21 42 15.9260653601	-25 51 26.592770500	J214215.9-255126	2139-260	2139-260	V	21 42 15.92606536	0.00040452	-25 51 26.5927705	0.0116300	0.119	53523.9	53523.9	53523.9	1	9

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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	RAJ2000 deg	DEJ2000 deg	e_RAJ2000 (...)	e_DEJ2000 arcsec	magBJ mag	e_ mag	magRF mag	e_ mag	magG mag	e_ mag	magGrvs mag	e_ [****ClosingBrace(s)Inserted****]
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e_

%20

%22>%5cFONT SIZE=-1magalphaEpoch
yr

deltaEpoch
yr

pmRA
mas/yr

e_
(...)

pmDE
mas/yr

e_
(...)

1 0.16221 42 15.93498-25 51 26.7188325.566396-25.857422 0.099 0.09920.713 0.30020.940 0.40020.856 0.40020.951 0.5002000.00002000.0000 0.0 0.0 0.0 0.0 %0a%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	RA_ICRS deg	e_ mas	DE_ICRS deg	e_ mas	Source	Plx mas	pmRA mas/yr	pmDE mas/yr	RADEcor	Dup	<FG> e-/s	e_ e-/s	<Gmag> mag	Var
1	0.052	21 42 15.926523622	-25 51 26.59364405	325.5663605151	6.538	-25.8573871233	7.947	6811519442251197056				0.978	0	1.9122e+02	3.4157e+00	19.821	NOT_AVAILABLE

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