Sky Coordinates

 IRAS90 has facilities for recognising coordinates in any of the following astronomical systems:

• Equatorial (FK4 and FK5, referenced to any specified equinox).
• Ecliptic (IAU 1980, referenced to any specified equinox).
• Galactic (IAU 1958)

Some applications have a COORDS parameter which allows the user to specify the coordinate system which is to be used by the application (eg when requesting sky positions from the user). Once a value has been assigned to a COORDS parameter the same value is used as the default for all subsequent applications, until a new value is assigned to a COORDS parameters. This is done by associating each COORDS parameter with the global parameter SKY_COORDS.