/ftp/cats/I/252



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I/252            The USNO-A2.0 Catalogue                     (Monet+ 1998)
The following files can be converted to FITS (extension .fit .fgz or .fiZ)
	out.sam
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Query from: http://vizier.cds.unistra.fr/viz-bin/VizieR?-source=I/252
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drwxr-xr-x 317 cats archive 8192 Feb 28 11:16 [Up] drwxr-xr-x 2 cats archive 4096 Jan 12 2023 [TAR file] -rw-r--r-- 1 cats archive 454 Dec 19 2022 .message -r--r--r-- 1 cats archive 4772 Jan 21 2000 ReadMe drwxr-xr-x 28 cats archive 4096 Sep 14 2010 USNO_A2 -rw-r--r-- 1 cats archive 1006 Mar 28 2008 +footg5.gif -rw-r--r-- 1 cats archive 13587 May 6 2012 +footg5.png -rw-r--r-- 1 cats archive 2967 Mar 28 2008 +footg8.gif -rw-r--r-- 1 cats archive 128642 May 6 2012 +footg8.png -rw-r--r-- 1 cats archive 450 Apr 8 2006 option.cat25 -r--r--r-- 1 cats archive 5600 Nov 2 1998 out.sam -r--r--r-- 1 cats archive 19366 Oct 8 1998 read.me -rw-r--r-- 1 cats archive 27301 Apr 8 2006 umax.lis
Beginning of ReadMe : I/252 The USNO-A2.0 Catalogue (Monet+ 1998) ================================================================================ USNO-A V2.0, A Catalog of Astrometric Standards Monet D. Bird A., Canzian B., Dahn C., Guetter H., Harris H., Henden A., Levine S., Luginbuhl C., Monet A.K.B., Rhodes A., Riepe B., Sell S., Stone R., Vrba F., Walker R. <U.S. Naval Observatory Flagstaff Station (USNOFS) and Universities Space Research Association (USRA) stationed at USNOFS. (1998)> ================================================================================ ADC_Keywords: Surveys ; Positional data Description: USNO-A2.0 is a catalog of 526,280,881 stars, and is based on a re-reduction of the Precision Measuring Machine (PMM) scans that were the basis for the USNO-A1.0 catalog. The major difference between A2.0 and A1.0 is that A1.0 used the Guide Star Catalog (Lasker et al. 1986, see Cat. I/220) as its reference frame whereas A2.0 uses the ICRF as realized by the USNO ACT catalog (Urban et al. 1997, see Cat. II/246>). A2.0 presents right ascension and declination (J2000, epoch of the mean of the blue and red plate) and the blue and red magnitude for each star. Usage of the ACT catalog as well as usage of new astrometric and photometric reduction algorithms should provide improved astrometry (mostly in the reduction of systematic errors) and improved photometry (because the brightest stars on each plate had B and V magnitudes measured by the Tycho experiment on the Hipparcos satellite). The basic format of the catalog and its compilation is the same as for A1.0, and most users should be able to migrate to this newer version with minimal effort.