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	3.919	18 05 16.00800	+48 15 46.4328	1350-09489262	271.316700	+48.262898			16.8	15.6	1950.383

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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	4.768	18 05 16.00080	+48 15 45.0108	EO0130-0198233	271.316670	+48.262503	14.17		2	49.16	21.5	0.25	15.34		1	47.49	21.4	1.17
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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	4.647	18 05 16.07088	+48 15 46.0656	N011003113087	271.316962	+48.262796	1993.623	14.02	0.31	14.38	0.32	3	8.15	0.04

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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	0.464	18 05 15.62688	+48 15 48.4704	1382-0313668	271.315112	+48.263464	51	157	1979.5	-12	-30	3	19.96			17.37	17.86
2	1.975	18 05 15.75072	+48 15 46.6632	1382-0313671	271.315628	+48.262962	999	230	1950.3	0	0	2	17.17	18.39
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%3cEM%3e2&%3cFONT%20COLOR=%27#CD5B45%27>%201.975&%3cFONT%20COLOR=%27#CD5B45%27>18%2005%2015.75072&%3cFONT%20COLOR=%27#CD5B45%27>%2b48%2015%2046.6632&1382-0313671&271.315628&%2b48.262962&999&230&1950.3&%20%20%20%20%200&%20%20%20%20%200&2&17.17&18.39&%20&%20&%20%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ662c012039ccdf&-out.add=.&-source=I/284/out&USNO-B1.0===1382-0313676&-out.orig=o' class='full'3 4.39118 05 16.10016+48 15 47.42281382-0313676271.317084+48.263173 669991972.4 0 0218.56      13.69 4 4.58318 05 16.05336+48 15 45.91081382-0313675271.316889+48.262753 951021972.4 0 0418.0516.4512.4212.58   5 8.42718 05 16.43736+48 15 44.90281382-0313680271.318489+48.2624739999991972.2 0 0419.6417.47  19.7318.16 6 9.38418 05 15.75480+48 15 39.13201382-0313672271.315645+48.260870 339991950.3 0 0218.9919.00       %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	0.466	18 05 15.626664	+48 15 48.47004	1382-0316202	..	271.3151111	+48.2634639	B	-12.0	1.0	-30.0	5.0	19.960	o			17.370	B
2	1.978	18 05 15.750672	+48 15 46.65996	1382-0316205	..	271.3156278	+48.2629611	B	0.0	0.0	0.0	0.0	17.170	o			18.390	e
3	4.390	18 05 16.099992	+48 15 47.41992	1382-0316210	..	271.3170833	+48.2631722	B	0.0	0.0	0.0	0.0	18.560	o
4	4.583	18 05 16.053336	+48 15 45.91008	1382-0316209	..	271.3168889	+48.2627528	B	0.0	0.0	0.0	0.0	12.420	B			12.580	B
5	8.428	18 05 16.437336	+48 15 44.89992	1382-0316214	..	271.3184889	+48.2624722	B	0.0	0.0	0.0	0.0	19.640	o			19.730	B
6	9.386	18 05 15.754656	+48 15 39.12984	1382-0316206	..	271.3156444	+48.2608694	B	0.0	0.0	0.0	0.0	18.990	o			19.000	e
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6	9.386	18 05 15.754656	+48 15 39.12984	1382-0316206	..	271.3156444	+48.2608694	B	0.0	0.0	0.0	0.0	18.990	o			19.000	e

%22>\EndTABLESORT

Note: This version of the GSC-II has no proper motions, but the limits on brightness which existed on GSC2.2 (F<18.5, B_j<19.5) were removed.

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	4.647	18 05 16.07112	+48 15 46.0692	N0ZX013087	271.316963	+48.262797	1993.623	14.02	14.38	15.96	15.08	3	8.15	0.04

%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	0.495	18 05 15.62688	+48 15 48.3084	271.315112	+48.263419	-14.1	-33.6			19.96			17.37	17.86	3	0
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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_ mag	alphaEpoch yr	deltaEpoch yr	pmRA mas/yr	e_ (...)	pmDE mas/yr	e_ (...)
1	0.495	18 05 15.62685	+48 15 48.3081	271.315112	+48.263419	0.133	0.133	19.960	0.400	17.370	0.400	17.354	0.400	15.589	0.500	1979.5000	1979.5000	-14.1	6.4	-33.6	6.4
2	4.669	18 05 16.05509	+48 15 45.7851	271.316896	+48.262718	0.115	0.115	14.382	0.300	14.015	0.300	14.100	0.400	13.737	0.500	1972.4700	1972.4700	0.3	5.2	-3.5	5.2
3	6.223	18 05 16.14435	+48 15 44.4058	271.317268	+48.262335	0.133	0.115	19.640	0.400	19.730	0.400	19.688	0.400	19.676	0.500	1968.6600	1968.6600	-55.3	6.4	-48.8	5.3

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