Altair IV was the inhabited fourth planet of the Altair system. This system was located in Sector 9, a region of space in the Alpha Quadrant. It was a Federation planet. (TOS: "Amok Time"; Star Trek II: The Wrath of Khan; TNG: "Eye of the Beholder", okudagram; DS9: "Prophet Motive"; PIC: "Maps and Legends")
In the 2340s, on stardate 22991.6, Lieutenant Darien Wallace was born on Altair IV. This lieutenant's personnel file appeared in a hallucination of Deanna Troi's. (TNG-R: "Eye of the Beholder", okudagram)
|Altair III • Altair IV • Altair VI|
Altair IV was referred to in the first draft script of Star Trek III: The Search for Spock, which established it as the place of origin of Altair water. The script also referred to it as "far away" from Earth.
According to Star Trek: Star Charts ("United Federation of Planets I") and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), Altair IV (Alpha Aquilae IV) was located in the Alpha Quadrant.
In Gene Roddenberry and D.C. Fontana's final draft script of the Star Trek: The Next Generation first season episode "Encounter at Farpoint", this planet was visited by the USS Hood. This was changed to Altair III for the aired episode.