Sigma Antares sector
The Sigma Antares sector was a region of space in the Alpha or Beta Quadrant.
In 2364, the USS Copernicus and the USS Omaha Nebraska were on missions in the sector. These missions were one part of tactical operations in this sector. (TNG: "Conspiracy", okudagram)
This sector was only mentioned in writing.
It was probable that this sector was named after a star system named Sigma Antares.