walled plain waning Water Carrier Water Jar Water Snake wavelength waxing WC star West, Comet Westerbork Observatory Whale Whipple Observatory Whirlpool Galaxy white dwarf white hole Widmanstätten figures Wild Duck William Herschel Telescope Willstrop telescope Wilson effect WIMPs Winchester Winged Horse winter solstice WIYN Telescope WLM WN star Wolf Wolf-Lundmark-Melotte galaxy Wolf-Rayet star Wolf sunspot number wormhole wrinkle ridge W Ursae Majoris star Würzburg antenna W Virginis star