AT: "xx" Eminiar was a star of the Alpha Quadrant. This star, the primary of the Eminiar system, was located within the NGC 321 star cluster.(TOS: "A Taste of Armageddon")
The location of Eminiar in the Milky Way Galaxy was depicted on a large Federation star chart in 2293. (Star Trek VI: The Undiscovered Country)
In 2367, the star appeared on a chart in Captain Benjamin Maxwell's ready room on the USS Phoenix. (TNG: "The Wounded")
In an alternate 2366, Eminiar was marked on a tactical situation monitor showing the fleet deployments in the Federation-Klingon War. (TNG: "Yesterday's Enterprise" display graphic)
The NGC 321 star cluster
The location of Eminiar on "The Explored Galaxy" wall chart
The location of Eminiar on a tactical situation monitor
On the tactical situation monitor, the location of Eminiar was displayed twice.
"The Explored Galaxy" depicted charted space within the Alpha Quadrant. The Tholian Assembly and Romulus/Remus were identified in dialog as being located in this quadrant. (DS9: "The Search, Part II", "Call to Arms") This chart was also seen in several Star Trek: The Next Generation and Star Trek: Deep Space Nine episodes set in the 24th century, from the year 2364 to 2370. These were TNG: "Conspiracy", "The Measure Of A Man", "The Emissary", "The Mind's Eye", "The Game", and DS9: "In the Hands of the Prophets", "Cardassians".