The Book of Lost Tales
Tolkien developed a list of names and meanings called the "Qenya Lexicon". Christopher Tolkien included extracts from this in an appendix to "The Book of Lost Tales", including mentions of specific stars, planets, and constellations in the entries: "Gong, Ingil, Mornië, Morwinyon, Nielluin, Silindrin, and Telimektar". The Sun was called Anor or Ur. The Moon was called Ithil or Silmo.