From their 1974 album, "Secret Treaties" (and 1988 album "Imaginos").
The song's lyrics are selected verses from a poem by Sandy Pearlman, the band's producer and mastermind behind their image, called "The Soft Doctrines of Immaginos". In the poem, which was later released under the BÖC moniker as "Imaginos", aliens known as Les Invisibles guide an altered human named Imaginos, also called Desdinova, through history, playing key roles that eventually lead to the outbreak of World War I. In "Astronomy", the character of Imaginos comes to realize his heritage and his role as the altered human. References are made to celestial objects throughout the song-- "The light that never warms" being the moon, "The Queenly flux" the constellation Cassiopeia, "My dog, fixed and consequent" being Sirius, the dog star. The "Four Winds Bar" may reference the Tropic of Cancer. All in all, it has Imaginos explaining his position as part of Les Invisibles.