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	0.835	17 06 44.07888	+18 21 25.7220	1050-08369001	256.683662	+18.357145			15.6	14.8	1954.507

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20%3cB%3e%3cFONT%20COLOR=%27#CD5B45%27>%20The%20current%20version%20includes%20only%20the%20North%20%28POSS-I%20plates%29%3cP%3e%0a

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	0.178	17 06 44.02272	+18 21 25.5816	EO0122-0143511	256.683428	+18.357106	14.35		1	6.37	21.6	0.42	16.25		1	10.07	20.7	1.90
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%3cEM%3e1&%3cFONT%20COLOR=%27#CD5B45%27>%200.178&%3cFONT%20COLOR=%27#CD5B45%27>17%2006%2044.02272&%3cFONT%20COLOR=%27#CD5B45%27>%2b18%2021%2025.5816&EO0122-0143511&256.683428&%2b18.357106&14.35&%20&%201&%20%20%206.37&%20%2021.6&%200.42&16.25&%20&%201&%20%2010.07&%20%2020.7&%20%201.90&%20%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ6628284d15e710&-out.add=.&-source=I/267/out&APM-ID===EO1127-0175642&-out.orig=o' class='full'2 0.95317 06 44.08800+18 21 25.7112EO1127-0175642256.683700+18.35714214.12   1 11.65 23.6 0.4516.18   1 10.33 20.6 2.06   %0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20construction%20of%20the%20%0a%3cB%3eGSC-II%20%0ais%20still%20in%20progress:%20this%0aversion%20has%20no%20proper%20motions,%20and%20the%20magnitude%20limits%20are%2018.5%20in%20F%20%28red%29%0aand%2019.5%20in%20J%20%28blue%29.%20The%20data%20are%20%3cB%3e%3cFONT%20COLOR=%27#0000CD%27>copyrighted,%20check%20%0athe%20%3cB%3edata%20use%20Policy.%0a%3cP%3e%0a

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	0.424	17 06 44.05440	+18 21 25.3980	N10331209973	256.683560	+18.357055	1996.446	13.59	0.42	15.22	0.41	3	12.70	0.59

%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/galaxy%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://www.nofs.navy.mil/data/fchpix/%20%3cBR%3e%0a%3cB%3e%3cFONT%20COLOR=%27#EE0000%27>%20Note%20that%20the%20star/galaxy%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	0.944	17 06 44.08536	+18 21 25.7832	1083-0284846	256.683689	+18.357162	143	55	1976.4	4	8	5	15.85	13.60	15.05	13.69	12.67
2	6.431	17 06 44.44800	+18 21 23.1624	1083-0284852	256.685200	+18.356434	999	105	1973.5	0	0	2		18.87			18.69
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%3cEM%3e2&%3cFONT%20COLOR=%27#CD5B45%27>%206.431&%3cFONT%20COLOR=%27#CD5B45%27>17%2006%2044.44800&%3cFONT%20COLOR=%27#CD5B45%27>%2b18%2021%2023.1624&1083-0284852&256.685200&%2b18.356434&999&105&1973.5&%20%20%20%20%200&%20%20%20%20%200&2&%20&18.87&%20&%20&18.69%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ6628284d15e710&-out.add=.&-source=I/284/out&USNO-B1.0===1083-0284840&-out.orig=o' class='full'3 7.32317 06 43.82400+18 21 18.66241083-0284840256.682600+18.3551849999991969.4 0 0220.73  18.44     4 8.12217 06 43.89288+18 21 17.50321083-0284842256.682887+18.3548621041451971.4 0 02  18.9419.54     5 9.16917 06 43.84416+18 21 16.60321083-0284841256.682684+18.3546127644751971.4 0 02  19.1619.69     6 9.29717 06 44.31816+18 21 33.71041083-0284851256.684659+18.3593649829991975.5 0 0219.64      17.19 %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	0.942	17 06 44.085336	+18 21 25.77996	1083-0289142	YM	256.6836889	+18.3571611	B	4.0	4.0	8.0	1.0	16.840	Y	15.760	Y	13.690	B	14.569	13.826	13.433
2	6.432	17 06 44.448000	+18 21 23.15988	1083-0289148	..	256.6852000	+18.3564333	B	0.0	0.0	0.0	0.0					18.870	e
3	7.325	17 06 43.824000	+18 21 18.65988	1083-0289136	..	256.6826000	+18.3551833	B	0.0	0.0	0.0	0.0	18.440	B
4	8.125	17 06 43.892664	+18 21 17.49996	1083-0289138	..	256.6828861	+18.3548611	B	0.0	0.0	0.0	0.0	19.540	B			18.940	e
5	9.173	17 06 43.843992	+18 21 16.59996	1083-0289137	..	256.6826833	+18.3546111	B	0.0	0.0	0.0	0.0	19.690	B			19.160	e
6	9.296	17 06 44.317992	+18 21 33.71004	1083-0289147	..	256.6846583	+18.3593639	B	0.0	0.0	0.0	0.0	19.640	o

%0a%22>ts_init('!ext/nomad1.exe_5');

Note: Zone -30/+50deg

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	0.473	17 06 44.05776	+18 21 25.4304	170644.0+182125		256.683574	+18.357064	15.728	6	14.569	13.827	13.434

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20This%20version%20of%20the%20%0a%3cB%3eGSC-II%0ahas%20no%20proper%20motions,%20but%20the%20limits%20on%20brightness%20which%20existed%20on%0a%20%28F<18.5,%20B_j<19.5%29%20were%20removed.%0a%25The%20data%20are%20%3cB%3e%3cFONT%20COLOR=%27#0000CD%27>copyrighted,%20check%0a%25the%20%3cB%3edata%20use%20Policy.%0a%3cP%3e%0a

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	0.424	17 06 44.05440	+18 21 25.3980	N3X4009973	256.683560	+18.357055	1996.446	13.59	15.22		13.39	3	12.70	0.59

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%22> _r