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	4.856	23 40 44.88888	+39 39 02.0916	1275-18558955	355.187037	+39.650581			16.3	15.8	1951.837

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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	APM-ID	RAJ2000 deg	DEJ2000 deg	rmag mag	l_	rClass	rStel	rDiam arcsec	rEll	bmag mag	l_	bClass	bStel	bDiam arcsec	b-r mag	Mflag
1	4.827	23 40 44.87208	+39 39 02.9412	EO0554-0412947	355.186967	+39.650817	20.00	L	0				17.20		1	9.12	16.0	-2.80
2	5.556	23 40 44.95080	+39 39 01.2816	EO0405-0016311	355.187295	+39.650356	15.96		1	12.25	15.0	0.46	16.99		1	9.39	16.6	1.03
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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC2.2	RA(ICRS) deg	DE(ICRS) deg	Epoch yr	Rmag mag	e_ mag	Bjmag mag	e_ mag	Class	a pix	e
1	4.923	23 40 44.89680	+39 39 01.6848	N00103225999	355.187070	+39.650468	1995.814	15.36	0.41	15.51	0.42	3	6.45	0.52

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20%3cB%3eUSNO-B%20Catalog%20presents%20positions,%20proper%20motions,%20%0amagnitudes%20un%20blue,%20red%20and%20infrared,%20as%20well%20as%20star%2fgalaxy%20estimators%0afor%201,045,175,762%20objects%20derived%20from%203,648,832,040%20separate%20observations.%0aThe%20data%20were%20taken%20from%20scans%20of%207,435%20Schmidt%20plates%0ataken%20from%20various%20sky%20surveys%20during%20the%20last%2050%20years.%3cBR%3e%0aUSNO-B1.0%20catalog%20was%20created%20by%20Dave%20Monet%20and%20collaborators%0aat%20http:%2f%2fwww.nofs.navy.mil%2fdata%2ffchpix%2f%20%3cBR%3e%0a%3cB%3e%3cFONT%20COLOR=%27#EE0000%27>%20Note%20that%20the%20star%2fgalaxy%20estimators%20may%20be%20mixed%20up%0a%20in%20dense%20regions.%0a%3cP%3e%0a

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	4.275	23 40 44.84016	+39 39 01.8432	1296-0538255	355.186834	+39.650512	583	73	1971.7	-10	-6	4	15.67	15.42	15.79		14.60
2	5.322	23 40 44.93136	+39 39 01.6416	1296-0538256	355.187214	+39.650456	437	253	1977.7	0	0	5	16.46	17.45	15.52	15.04	14.90
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%3cEM%3e2&%3cFONT%20COLOR=%27#CD5B45%27>%205.322&%3cFONT%20COLOR=%27#CD5B45%27>23%2040%2044.93136&%3cFONT%20COLOR=%27#CD5B45%27>%2b39%2039%2001.6416&1296-0538256&355.187214&%2b39.650456&437&253&1977.7&%20%20%20%20%200&%20%20%20%20%200&5&16.46&17.45&15.52&15.04&14.90%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	4.273	23 40 44.839992	+39 39 01.83996	1296-0561955	YM	355.1868333	+39.6505111	B	-10.0	16.0	-6.0	2.0	17.040	Y	16.210	Y	15.420	e	16.135	15.233	14.890
2	5.322	23 40 44.931336	+39 39 01.64016	1296-0561956	..	355.1872139	+39.6504556	B	0.0	0.0	0.0	0.0	15.520	B			15.040	B

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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC2.3	RAJ2000 deg	DEJ2000 deg	Epoch [****ClosingBrace(s)Inserted****]
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Epoch

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

a
pixe

1 4.92623 40 44.89704+39 39 01.6848N08Q005999355.187071+39.6504681995.81415.3615.51  15.213 6.45 0.52 %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	4.499	23 40 44.86008	+39 39 01.6776	355.186917	+39.650466	-3.0	-9.1	16.135	14.890	15.67	15.79	15.42		14.60	5	0
2	4.666	23 40 44.87448	+39 39 01.7208	355.186977	+39.650478	-15.5	3.0	16.135	14.890	16.46	15.52	17.45	15.04	14.90	6	0

%0a%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	ID	RAICRS deg	DEICRS deg	pmRAp mas/yr	pmDEp mas/yr	pmRAx mas/yr	pmDEx mas/yr	Fmag mag	Bjmag mag	Vmag [****ClosingBrace(s)Inserted****]
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Vmag

%20

%22>%5cFONT SIZE=-1magNmag
mag

Jmag
mag

e_
mag

Hmag
mag

e_
mag

Kmag
mag

e_
mag

2Mkey

Bmag
mag

Rmag
mag

Fld

dT
yr

fg

fs

M

1 4.61923 40 44.87040+39 39 01.7101XPM 259-0845125355.186960+39.650475 -1.46 -5.92 -1.35 -5.4615.36315.510  15.21216.135 0.12115.233 0.14014.890 0.132 43991182716.315.8 29247.05798000M %0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20%3cP%3e%0a

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_ mag	alphaEpoch yr	deltaEpoch yr	pmRA mas/yr	e_ (...)	pmDE mas/yr	e_ (...)
1	4.499	23 40 44.86004	+39 39 01.6779	355.186917	+39.650466	0.075	0.075	15.790	0.400	15.420	0.400	15.506	0.400	15.141	0.500	1987.5000	1987.5000	-3.0	4.0	-9.1	4.0
2	4.666	23 40 44.87446	+39 39 01.7212	355.186977	+39.650478	0.071	0.071	15.510	0.300	15.363	0.300	15.390	0.400	15.194	0.500	1988.8500	1988.8500	-15.5	4.1	3.0	4.1

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20%3cP%3e%0a