the spatial coverage of a resource the spectral coverage of a resource the temporal coverage of a resource a coverage area of the sky Multiple occurances imply a coverage that is a union of the regions given (i.e. a logical "or", according to RM). The spatial (angular) resolution that is typical of the observations of interest, in decimal degrees. The intrinsic size scale, given in arcseconds, associated with data items contained in a resource. Both data archives and catalogs have an intrinsic scale size. For example, a source catalog created from an instrument with one degree angular resolution would have a RegionOfRegard of 0.5 degree, meaning that if one is searching for information pertinent to a given position, objects in this catalog within 0.5 degree of the position of interest would need to be included. For an image archive the RegionOfRegard corresponds to the image field of view. a coverage area covering the entire sky The International Celestial Reference System Equatorial coordinates in the FK5 system (J2000) Equatorial coordinates in the FK4 system (J1950) ecliptic coordinates (J2000) Galactic Coordinates (J2000) Super-Galactic Coordinates (J2000) a coverage area of the sky characterized by a range of longitude and latitude. a coordinate system frame The range in longitude The range in latitude The minimum angle The maximum angle a coverage area of the sky characterized by a central position and angular radius a coordinate system frame the position of the center of the circle/cone. the radius of the circle in degrees. the longitude component of the sky position the latitude component of the sky position The earliest temporal coverage of the resource. If not provided, the start time is not known. The latest temporal coverage of the resource. If not provided, the end time is not known (e.g. because information continues to be added to the resource). The temporal resolution that is typical of the observations of interest, in seconds. a named spectral region of the electro-magnetic spectrum. a range of the electro-magnetic spectrum specified by a lower and upper wavelength limit. The spectral resolution that is typical of the observations of interest, given as a ratio of the wavelength width (delta-lambda) to the observing wavelength (lambda). wavelength >= 10 mm; frequency <= 30 GHz. 0.1 mm <= wavelength <= 10 mm; 3000 GHz >= frequency >= 30 GHz. 1 micron <= wavelength <= 100 micons 0.3 microns <= wavelength <= 1 micon; 300 nm <= wavelength <= 1000 nm; 3000 Angstroms <= wavelength <= 10000 Angstroms 0.1 microns <= wavelength <= 0.3 micon; 1000 nm <= wavelength <= 3000 nm; 1000 Angstroms <= wavelength <= 30000 Angstroms 100 Angstroms <= wavelength <= 1000 Angstroms; 12 eV <= Energy <= 120 eV 0.1 Angstroms <= wavelength <= 100 Angstroms; 0.12 keV <= energy <= 120 keV energy >= 120 keV The minimum wavelength The maximum wavelength