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Specification of position

Right ascension (as well as ecliptic and galactic longitude) may be specified as HH:MM:SS.sss or as DD.dddd (decimal degrees), declination (and ecliptical and galactic latitude) as DD:MM:SS.sss or as DD.dddd. If no unit is given, RA is assumed to be specified in hours, minutes, seconds and DEC in degrees, arcminutes, arcseconds. The hours, minutes and seconds (degrees, arcminutes, arcseconds) parts may contain a decimal point. Right ascension (longitude) intervals bracketing 24hrs (360degrees) may be specified unambiguously. (Arc)minutes and (arc)seconds are allowed to exceed 60. Some examples:

for RA: 10:30:00 = 10.5: = 157.5 ; for DEC: 10:30:00 = 10.5: = 10.5

RA=345 TO 15DEG is equivalent to RA=23: TO 1:, and also to RA=23 TO 24, 0 TO 1.

Units (HR, MIN, SEC, DEG, ARCMIN, ARCSEC, RAD, etc.) may be used instead of colons.

Note that the generic position keywords POS (EQPOS, GAPOS, ECPOS) and BOX (EQBOX, GABOX, ECBOX) may be used to specify a position in any coordinate system with a search radius or a search rectangle (see also section and section ). If a BOX is specified in a SELECT command, the units of the given box width depend on the coordinate system. However, the default unit for (maximum) radius and for the (maximum) height of a box is always degrees.

The default list format of positions may be set by the command DEFAULT (see section ) or by the qualifier /FORMAT (see Tables QU and KEY). The initial value of format is MS ( hms/ ' ") for equatorial coordinates and DEG (decimal degrees) for ecliptic and galactic coordinates.


Fri Aug 12 10:24:53 BST 1994