Ceres and Pluto received planetary symbols, as they were considered to be planets when they were discovered. By the time the others were discovered, planetary symbols had mostly fallen out of use among astronomers. Unicode includes symbols for Quaoar , Sedna , Orcus , Haumea , Eris , Makemake , and Gonggong that are primarily used by astrologers: they were devised by Denis Moskowitz, a software engineer in Massachusetts. NASA has used his Haumea, Eris, and Makemake symbols, as well as the traditional astrological symbol for Pluto when referring to it as a dwarf planet. Symbols have been proposed for the next-largest named candidates, but do not have consistent usage among astrologers. The Unicode proposal for Quaoar, Orcus, Haumea, Makemake, and Gonggong mentions the following symbols for named objects over 600 km diameter: Salacia , Varda , Ixion , Gǃkúnǁʼhòmdímà and Varuna .