WCelestial coordinate system
WAlmucantar
WAzimuth
WBarycenter
WCircumpolar star
WColure
WDeclination
WEarth-centered inertial
WEcliptic
WEcliptic coordinate system
WEquator
WCelestial equator
WEquatorial coordinate system
WFirst Point of Aries
WGalactic coordinate system
WGalactic quadrant
WGeocentric model
WHorizon
WHorizontal coordinate system
WHour angle
WHour circle
WMeridian (astronomy)
WNadir
WNorthern celestial hemisphere
WOrbital pole
WCelestial pole
WPosition angle
WRight ascension
WRotating reference frame
WSouthern celestial hemisphere
WCelestial sphere
WSubsolar point
WVertical circle
WZenith
WZodiac