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	5.038	16 49 49.87272	+05 35 58.2720	0900-09001812	252.457803	+05.599520			15.7	14.1	1954.342
2	7.391	16 49 49.72416	+05 35 57.4620	0900-09001765	252.457184	+05.599295			16.2	15.5	1954.342

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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	4.343	16 49 49.91952	+05 35 58.4304	EO1056-0209040	252.457998	+05.599564	13.80		1	34.33	26.2	0.60	16.11		1	20.39	30.3	2.30
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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	4.820	16 49 49.88640	+05 35 58.3512	N103101010328	252.457860	+05.599542	1993.529	13.65	0.41	14.72	0.42	3	11.40	0.62

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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	0.418	16 49 50.15208	+05 36 00.6732	0956-0274030	252.458967	+05.600187	567	134	1975.8	0	0	2	17.46				14.18
2	4.531	16 49 50.47536	+05 36 01.2528	0956-0274032	252.460314	+05.600348	999	999	1971.3	0	0	2	19.65		20.81
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%3cEM%3e2&%3cFONT%20COLOR=%27#CD5B45%27>%204.531&%3cFONT%20COLOR=%27#CD5B45%27>16%2049%2050.47536&%3cFONT%20COLOR=%27#CD5B45%27>%2b05%2036%2001.2528&0956-0274032&252.460314&%2b05.600348&999&999&1971.3&%20%20%20%20%200&%20%20%20%20%200&2&19.65&%20&20.81&%20&%20%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ663c76202b153f&-out.add=.&-source=I/284/out&USNO-B1.0===0955-0275771&-out.orig=o' class='full'3 5.02116 49 49.87200+05 35 58.33320955-0275771252.457800+05.599537 911101977.6 0 0516.0214.4814.5213.3011.83 4 5.35816 49 50.50272+05 36 02.70000956-0274034252.460428+05.6007501642341975.8 0 0220.38      18.42 5 8.87116 49 50.73936+05 36 03.31200956-0274037252.461414+05.6009202195481978.7 0 03  19.7620.7719.60   6 9.31416 49 49.60152+05 35 56.85000955-0275765252.456673+05.599125208 441968.7 -38 -12316.6115.66    15.90 %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	0.417	16 49 50.152008	+05 36 00.66996	0956-0277965	YM	252.4589667	+05.6001861	B	0.0	0.0	0.0	0.0	18.350	o	17.210	Y			16.117	14.336	14.038
2	1.376	16 49 50.233872	+05 36 01.54404	0956-0277966	.M	252.4593078	+05.6004289	M	0.0	0.0	0.0	0.0							15.330	15.678	15.246
3	4.530	16 49 50.475336	+05 36 01.24992	0956-0277968	..	252.4603139	+05.6003472	B	0.0	0.0	0.0	0.0	20.810	B
4	5.023	16 49 49.872000	+05 35 58.32996	0955-0279954	YM	252.4578000	+05.5995361	B	0.0	0.0	0.0	0.0	17.250	Y	16.740	Y	13.300	B	15.163	13.881	13.490
5	5.357	16 49 50.502672	+05 36 02.70000	0956-0277970	..	252.4604278	+05.6007500	B	0.0	0.0	0.0	0.0	20.380	o
6	8.870	16 49 50.739336	+05 36 03.30984	0956-0277973	..	252.4614139	+05.6009194	B	0.0	0.0	0.0	0.0	20.770	B			19.600	B
7	9.317	16 49 49.601328	+05 35 56.85000	0955-0279948	..	252.4566722	+05.5991250	B	-38.0	5.0	-12.0	1.0	16.610	o			15.660	e
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7	9.317	16 49 49.601328	+05 35 56.85000	0955-0279948	..	252.4566722	+05.5991250	B	-38.0	5.0	-12.0	1.0	16.610	o			15.660	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	4.820	16 49 49.88640	+05 35 58.3512	N3T0010328	252.457860	+05.599542	1993.529	13.65	14.72	15.15	13.69	3	11.40	0.62

%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	1.096	16 49 50.10456	+05 36 00.6876	252.458769	+05.600191	-20.5	-3.0	15.331	15.247	17.46				14.18	4	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	1.096	16 49 50.10452	+05 36 00.6880	252.458769	+05.600191	0.072	0.072	17.460	0.400	17.855	0.500	17.721	0.400	17.946	0.500	1995.5600	1995.5600	-20.5	5.3	-3.0	5.3
2	5.199	16 49 50.49076	+05 36 02.7068	252.460378	+05.600752	0.163	0.163	20.380	0.400	17.992	0.500	18.064	0.400	16.394	0.500	1975.8900	1975.8900	-4.6	7.5	-3.1	7.5
3	5.297	16 49 49.85281	+05 35 58.2968	252.457720	+05.599527	0.063	0.063	14.721	0.300	13.651	0.300	13.870	0.400	12.994	0.500	1991.8100	1991.8100	-8.9	3.9	-1.7	3.9
4	8.726	16 49 50.72233	+05 36 03.5887	252.461343	+05.600997	0.133	0.133	20.770	0.400	19.600	0.400	19.829	0.400	18.884	0.500	1978.7400	1978.7400	-7.0	7.6	3.7	7.6
5	9.579	16 49 49.58908	+05 35 56.6119	252.456621	+05.599059	0.133	0.133	16.610	0.400	15.660	0.400	15.864	0.400	15.072	0.500	1968.7100	1968.7100	-44.6	6.5	-20.8	6.5

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