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	0.394	04 01 56.45208	+19 28 07.9428	1050-01113397	060.485217	+19.468873			15.8	13.6	1950.936
2	7.685	04 01 56.17752	+19 28 14.1204	1050-01113371	060.484073	+19.470589			19.7	18.8	1950.936

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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	0.219	04 01 56.45088	+19 28 07.7232	EO0223-0169476	060.485212	+19.468812	13.84		1	29.79	18.6	0.12	16.06		1	16.84	13.6	2.22
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Note: The construction of the GSC-II is still in progress: this version has no proper motions, and the magnitude limits are 18.5 in F (red) and 19.5 in J (blue). The data are copyrighted, check the data use Policy.

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	0.587	04 01 56.45208	+19 28 08.1444	N30220136519	060.485217	+19.468929	1991.782	13.85	0.30	16.19	0.27	3	7.92	0.22

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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	0.248	04 01 56.45136	+19 28 07.7700	1094-0044421	060.485214	+19.468825	71	132	1974.7	0	0	5	15.84	13.53	15.06	13.28	12.28
2	4.745	04 01 56.46072	+19 28 02.8308	1094-0044422	060.485253	+19.467453	612	80	1970.4	0	0	2		19.12		18.50
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%3cEM%3e2&%3cFONT%20COLOR=%27#CD5B45%27>%204.745&%3cFONT%20COLOR=%27#CD5B45%27>04%2001%2056.46072&%3cFONT%20COLOR=%27#CD5B45%27>%2b19%2028%2002.8308&1094-0044422&060.485253&%2b19.467453&612&%2080&1970.4&%20%20%20%20%200&%20%20%20%20%200&2&%20&19.12&%20&18.50&%20%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ6643acc73a02a3&-out.add=.&-source=I/284/out&USNO-B1.0===1094-0044420&-out.orig=o' class='full'3 4.90304 01 56.39736+19 28 12.39241094-0044420060.484989+19.4701091058781980.6 0 0419.23  18.4117.2918.27 4 5.09804 01 56.57880+19 28 02.75161094-0044423060.485745+19.467431 399991978.1 166 -2703  20.0814.2318.65   5 7.05804 01 56.16000+19 28 13.19161094-0044417060.484000+19.4703313299991964.5 0 0320.5119.4219.66     6 7.55704 01 56.99016+19 28 08.75281094-0044424060.487459+19.4690985275691973.3 0 0220.45      18.81 7 7.56704 01 56.38008+19 28 15.05281094-0044419060.484917+19.4708481772201982.1 -22 264  19.0119.5918.6518.04 8 7.69104 01 56.28216+19 28 14.83321094-0044418060.484509+19.4707879999991977.5 -416 -303  20.0718.5519.54   %0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20Naval%20Observatory%20Merged%20Astrometric%20Dataset%20%28NOMAD%29%20contains%0aastrometric%20and%20photometric%20data%20for%20over%201%20billion%20stars%20derived%20from%0athe%20Hipparcos%20%28I/239%29,%20Tycho-2%20%28I/259%29,%20UCAC2%20%28I/289%29,%20and%20USNO-B1.0%0a%28I/284%29%20catalogs%20for%20astrometry%20and%20optical%20photometry,%20supplemented%0aby%202MASS%20%28II/246%29%20near-infrared%20photometry.%3cBR%3e%0a%3cFONT%20SIZE=%27-1%27%3eAn%20efficient%20remote%20query%20program%20%3cB%3efindnomad1%20is%0aavailable%20in%20the%20cdsclient%20%0apackage,%20for%20Unix/Linux%20platforms%0a%3cP%3e%0a

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	0.249	04 01 56.451336	+19 28 07.77000	1094-0044972	YM	060.4852139	+19.4688250	B	0.0	0.0	0.0	0.0	16.690	Y	16.750	Y	13.280	B	15.079	14.292	13.637
2	4.746	04 01 56.460672	+19 28 02.83008	1094-0044973	..	060.4852528	+19.4674528	B	0.0	0.0	0.0	0.0					18.500	B
3	4.901	04 01 56.397336	+19 28 12.38988	1094-0044971	..	060.4849889	+19.4701083	B	0.0	0.0	0.0	0.0	18.410	B			17.290	B
4	5.099	04 01 56.578656	+19 28 02.75016	1094-0044974	..	060.4857444	+19.4674306	B	166.0	1.0	-270.0	132.0	14.230	B			18.650	B
5	7.057	04 01 56.160000	+19 28 13.19016	1094-0044968	..	060.4840000	+19.4703306	B	0.0	0.0	0.0	0.0	19.660	B			19.420	e
6	7.554	04 01 56.989992	+19 28 08.74992	1094-0044975	..	060.4874583	+19.4690972	B	0.0	0.0	0.0	0.0	20.450	o
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6	7.554	04 01 56.989992	+19 28 08.74992	1094-0044975	..	060.4874583	+19.4690972	B	0.0	0.0	0.0	0.0	20.450	o

%22>\Ahref='VizieR-5?-ref=VIZ6643acc73a02a3&-out.add=.&-source=I/297/out&NOMAD1===1094-0044970' class='full'7 7.56404 01 56.380008+19 28 15.049921094-0044970..060.4849167+19.4708472B -22.0 6.0 26.0 8.019.590B    18.650B         8 7.68904 01 56.281992+19 28 14.829961094-0044969..060.4845083+19.4707861B -416.0 64.0 -30.0 56.018.550B    19.540B         %0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20Zone%20-30/%2b50deg%3cP%3e%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	CMC14	f_	RAICRS deg	DEICRS deg	r'mag mag	Nt	Jmag mag	Hmag mag	Ksmag mag
1	0.224	04 01 56.45952	+19 28 07.3560	040156.4+192807		060.485248	+19.468710	16.405	1	15.079	14.293	13.638

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Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC2.3	RAJ2000 deg	DEJ2000 deg	Epoch yr	Fmag mag	jmag mag	Vmag mag	Nmag mag	Class	a pix	e
1	0.589	04 01 56.45232	+19 28 08.1480	N9ZB006519	060.485218	+19.468930	1991.782	13.85	16.19	16.11	14.07	3	7.92	0.22
2	8.018	04 01 56.38032	+19 28 15.5100	N9ZB009529	060.484918	+19.470975	1985.954		19.94			3	4.66	0.35

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