The Mirtonian Constellation is a region of space which has at least twice been involved in the Transformers' constant warring.
During the Generation 2 timeframe, Optimus Prime fought Megatron in Sector 17 of the constellation and was catastrophically damaged. His subsequent reconstruction incorporated Laser Rod technology and is possibly the point at which he was given the Reconfiguration Matrix.
Note: The Star Brigade subset of G.I. Joe included a Lunartix alien named Carcass, whose home is listed as Quadrant 4 of the planet Mirtonia. It is possible that this planet is what gives the Mirtonian Constellation its name; it is also possible that there is no relationship between the two.