Astronomical Data Center

ADCADC/CDS Standard Document for Catalog:
/external/astrom/E1001/

The ADC has expanded its resources in order to better serve our users, we have developed a new category called "external" to complement our catalogs and journal table directories. You can access the data set described here through the URL:
http://aps.umn.edu/About/aps_catalog.html.

The following is an abbreviated "ReadMe" document that describes this external data set.
E/I/1	APS Catalog of the POSS I		  (Humphreys+ 1996)
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APS Catalog of the POSS I
	Humphreys R. M., Odewahn S. C., Aldering G., Cornuelle C. S., 
        Larsen J., Thurmes P., Landau R., Ghigo F. D., Zumach W., 
        Stockwell E. B., Pennington R. L., Cabanela J., Bryja C., 
        Musukula S.
	<unpublished (1996)>
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ADC_Keywords: Positional data; Historical catalog; Photographic catalog; 
              Combined data; Cross identifications; Surveys; Photometric data; 
              On-line catalog; External catalog

Location: http://aps.umn.edu/About/aps_catalog.html  

Description:
	This catalog contains positions, magnitudes, colors, and classes for 
        over 100 million stars and 20 million galaxies, as derived from 
        digitized Palomar Sky Survey (POSS) photographic plates.  The 
        operation of the Automated Plate Scanner (APS) and the scanning 
        procedures and parameters are described in detail in Pennington et al.
        (1993).  The APS catalog is a fully-documented searchable on-line 
        database accessible through the URL 
        http://aps.umn.edu/About/aps_catalog.html.  All 664 fields with |b| > 20 
        degrees and both the blue and red (O and E) plates in each field have 
        been scanned in threshold densitometry mode.  Positions are calibrated 
        to the Lick NPM Catalog and the ACRS, producing full-plate solutions 
        with an rms of 0.2 - 0.3 arcseconds in RA and Dec across each plate.  
        Stellar photometry is good to about 0.2 mag in the range 14 - 20 mag 
        (Larsen and Humphreys, 1996), and galaxy magnitudes show a typical rms
        scatter of 0.2 - 0.3 mag (Odewahn and Aldering, 1995).  Star-galaxy 
        separation is achieved with an artificial neural network algorithm with 
        an accuracy above 90% between mag 12 and 19.5 (Odewahn, 1995).  
        Customized finder charts can also be generated on-line from the 
        catalog entries.  The APS Project is supported by the NSF, NASA, and 
        the University of Minnesota.

References:
	Larsen, J. A., and Humphreys, R. M. 1996, "Formation of the Galactic 
		Halo...Inside and Out, ASP Conference Series, Vol. 92, 1996, 
                Heather Morrison and Ata Sarajedini, eds.," 88.
	Odewahn, S. C. 1995, PASP, 107, 770. =1995PASP..107..770O
	Odewahn, S. C., and Aldering, G. 1995, AJ, 110, 2009. 
                =1995AJ....110.2009O
	Pennington, R. L., Humphreys, R. M., Odewahn, S. C., Zumach, W., and 
		Thurmes, P. M. 1993, PASP, 105, 521. =1993PASP..105..521P
	
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(End)             Gail L. Schneider [SSDOO/ADC]          26-Feb-1997
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