Ranna an aeir ("The Constellations") is the title of a medieval Irish astronomical tract, thought to date from c.1500–1550? It was written in Early Modern Irish, with some words in English and Latin.
See also An Irish Astronomical Tract
References
Manuscript Sources National Library of Scotland; Advocates 72.1.2 olim Gaelic II (The National Library of Ireland holds a microfilm copy (n. 307, p. 452).)
Edition A. O. Anderson, Ranna an aeir [The Constellations] in Revue Celtique, Ed. Henri d'Arbois de Jubainville, Volume 30, Paris, F. Vieweg (1909) page 404–417