sub1 USNO-B1.0 Catalog Search Program

By default, only the brightest 100 objects (or closest 100, if the -s p option is used) are returned. Use the -n option to increase this number.

Output is to standard output, unless the -w flag is set, in which case it goes to objectname.ub1 or search.ub1.

The UB1 number is the zone ((South Polar Distance in degrees by 1/10th's) * 10) followed by the seven-digit sequence number of the star within the RA-sorted zone. This number will change with each release of the USNO B catalog.

Before you can use this program, the path to the directory containing the region files must be set. The default is to use the value of the variable ub1path in the source code file libwcs/ubcread.c, which is initially set to /data/ub1, which is where the catalog resides at the Center for Astrophysics. If you do not have access to the source code and need to change the path, you can set the environment variable UB1_PATH to the directory containing the region files, and that will override the file setting.

Command Line Arguments

In addition to those arguments to scat which apply to all catalogs, there are two USNO-B1.0-specific parameters which can be set on the command line. If they appear, they must come after -c ub1 or sub1 on the command line. minid=number If the object is found on fewer than this many plates, where the range is 2-5, it is left off the list. All Tycho-2 stars, where the catalog value of this number is set to zero, are included unless number is negated. The default value set in the file libwcs/ubcread.c is 0. For the most accurate positions, use minid=4. minpmqual=number If the proper motion quality flag is less than this number, proper motion is never added to the catalog position. The range is 1-9 from the catalog, or 10 if the proper motion is from the Tycho-2 Catalog. Setting this to 11 will never add proper motion. The default value set in the file libwcs/ubcread.c is 3. For the best proper motions, use minpmqual=9.

CGI Queries and Parameters

sub1 can be used remotely as a CGI executable.

Examples

Search with results to standard output Search with results to a file Find closest star Find stars by number Match stars in input catalog Search over the web with results to standard output Find objects found on 4 or more plates

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Last updated 6 October 2003 by Doug Mink dmink@cfa.harvard.edu