Ontarus sector

Ontarus sector is the location of the asteroid Opelon, held by the Cylons. It is either nearby or adjacent to the both the Omicron and Talus sectors.

Jaspar leads the Fleet to this system with the promise of encountering a colony from Earth. They find out that a system is controlled by Cylons, which launch an attack on Galactica and her fleet (I Have Seen Earth).