Equinox

Equinox was produced by the band at Paragon in Chicago, with Barry Mraz engineering and co-remixing and Doug Sax mastering. Most of the songs are by DeYoung, with Young and Curulewski sharing credits, and "Prelude 12" is an instrumental by Curulewski. "Lorelei" was released as a single in February 1976 and reached number 27, and "Light Up" followed in July 1976. The album reached number 58 in the United States and number 14 in Canada, was certified gold in the United States in 1977 and platinum in Canada.

AllMusic gave it two and a half stars and the Rolling Stone Album Guide one. In a 2020 Ultimate Classic Rock retrospective, DeYoung ranked it fourth in the Styx catalog, and Shaw called its second side highly underrated. Music Street Journal's Gary Hill called the closing epic one of the quintessential rock tracks of the 1970s.