> I'm not questioning that some gay men regarded themselves as a "third sex"
> and wanted to be called Uranians (after the planet rather than the muse).
> that goes back no earlier than the mid-1800s, and there's a much longer
> tradition of Urania as the muse of astronomy.

I just performed a quick search and found a page that looks authoratative.
Anyone interested can explore further.

   Rick Parker


Karl Heinrich Ulrichs (1825-1895)

Beginning in 1864, under the pseudonym "Numa Numantius," Ulrichs wrote a
series of five booklets called "Researches into the Riddle of Love Between
Men" in which he began to develop a theory of homosexuality. Men who love
men, he argued, consist of a female soul trapped in a male body. They are
neither male nor female in the conventional sense, but rather a third sex,
which he called "Urning"--or "Uranian"--after the famous myth in Plato's
Symposium in which Pausanias calls love between men "the beautiful love, the
Heavenly love, the love belonging to the Heavenly Muse Urania."