The quasar-like Murasaki 312 in 2267
A quasar is a specific type of astronomical object formed by matter falling into a super-massive black hole. The resulting energy is released as X-rays in all directions. However, the X-ray release is most intense directly above or below the galactic plane. Observed from this view, the resulting bright object is known as a Quasar.
During the original five-year mission of the USS Enterprise (NCC-1701), Captain James T. Kirk was under standing orders to investigate all quasars, and quasar-like phenomena. In 2267, the Enterprise encountered Murasaki 312, a quasar-like electromagnetic phenomenon. (TOS: "The Galileo Seven")
In 2367, Worf informed Data about the long range sensoring on the Murasaki 312, a quasar-like phenomenon. (TNG: "Data's Day")
In 2370, Captain Jean-Luc Picard received a priority one message from Admiral Blackwell inquires to the current status – conducting surveys of the Mekoria Quasar. (TNG: "The Pegasus")
In 2376, Tuvok described Kelemane's planet as having a high rate of rotation "like a quasar". (VOY: "Blink of an Eye") Also, Icheb informed Seven of Nine that when he was on the Borg cube: "never thought about what was outside, such as pulsars, quasars, and nebulas...". (VOY: "Child's Play")