This is the riddle of the star-crossed lover,
His insignia etched forever,
Whose name foretold unhappiness,
Proving that the ends justify the means,
To the North: Round like an empennage orb,
To the East: Half delta, anyhow a pair I was,
To the South: A dual neb, I render hue two,
To the West: Wing metacarpi, white swan ulna nigh,
I myself: Was a star-crossed lover,
Who/what am I?
You are ...
... Sadr or Gamma Cygni, a star in the constellation of Cygnus.
The fourth line says that "the ends justify the means", and if we take the "ends" of the words in the second stanza, we get:
To the North: Deneb (Alpha Cygni)
To the East: Fawaris (Delta Cygni)
To the South: Albireo (Beta Cygni)
To the West: Gienah (Epsilon Cygni)
The Cygnus constellation looks a bit like a cross with these stars lying more or less in the given celestial directions. In the middle is Sadr or Gamma Cygni.
There are some more hints: Albireo is a dual star; Fawaris has "delta" in its phrase; Cygnus means "swan" and probably some that I have missed.
As for Sadr itself, "His insignia etched forever" spells its name in the same fashion as the names of its neighbours; It has "sad" in its name, thereby foretelling unhappiness, and using the Phonetic alphabet to describe the R, we get "Sad Romeo", one of Shakespeare's star-crossed lovers. And, of course, Cygnus itself is a "star cross".