Find sources in a database within specified radius of specified target
Uses QuerySimbad to translate target name to RA and Dec, and then uses
DBCIRCLE() to find any entries within specified radius. Database must
include items named 'RA' (in hours) and 'DEC' (in degrees) and must
have previously been opened with DBOPEN
list = DBTARGET(target, [radius, sublist, /SILENT, DIS= ,/TO_B1950 ] )
TARGET - A scalar string giving an astronomical target name, which
will be translated into J2000 celestial coordinates by QuerySimbad
RADIUS - Radius of the search field in arc minutes, scalar.
Default is 5 arc minutes
SUBLIST - Vector giving entry numbers in currently opened database
to be searched. Default is to search all entries
LIST - Vector giving entry numbers in the currently opened catalog
which have positions within the specified search circle
LIST is set to -1 if no sources fall within the search circle
!ERR is set to the number sources found.
DIS - The distance in arcminutes of each entry specified by LIST
to the search center specified by the target.
Optional Keyword Input
/SILENT - If this keyword is set, then DBTARGET will not print the
number of entries found at the terminal
/TO_B1950 - If this keyword is set, then the SIMBAD J2000 coordinates
are converted to B1950 before searching the database
NOTE: The user must determine on his own whether the database
is in B1950 or J2000 coordinates.
The database must have items 'RA' (in hours) and 'DEC' (in degrees).
Alternatively, the database could have items RA_OBJ and DEC_OBJ
(both in degrees)
(1) Use the HST_CATALOG database to find all HST observations within
5' (the default) of M33
IDL> list = dbtarget('M33')
(2) As above but restrict targets within 2' of the nucleus using the
IDL> sublist = dbfind('config=WFPC2')
IDL> list = dbtarget('M33',2,sublist)
Written W. Landsman SSAI September 2002
Propagate /SILENT keyword to QuerySimbad W. Landsman Oct 2009
Make sure a database is open W.L. Oct 2010