Ragnar is the second largest planet in all of the Twelve Colonies's star systems and is a gas giant that orbits both the Helios Gamma and Helios Delta star systems, having been dislodged from its former orbit in the Helios Gamma system by the planet Ophion. During the "Miniseries", then-Commander Adama takes the Galactica there for supplies and weapons from the Ragnar Anchorage, which was in low orbit around the planet. Ragnar's natural radiation was discovered to be damaging to the Cylons, who avoided the planet and allowed the refugee fleet to hide here temporarily before fleeing the system. Ragnar's atmosphere is mined for its plentiful hydrocarbons that are used at the weapons depot that orbits it.
Ragnar Anchorage is a Colonial munitions depot suspended in the upper atmosphere of the gas giant Ragnar. The Colonial Fleet learned that the atmosphere of the planet Ragnar emitted a kind of radiation that adversely affected Cylon technology and cloaked ships residing within the storm. When the Cylons launch their attack on the Twelve Colonies, the Battlestar Galactica was without any munitions for her main and point-defence batteries, having dumped them as part of her decommissioning ceremonies prior to the battle. Colonel Saul Tigh determined that Ragnar Anchorage offers the best opportunity for re-arming the ship, based on its listing in an old directory of military supply depots.
While at Ragnar Anchorage, Galactica obtained enough munitions to completely re-arm her guns, and she also collected a number of Class-D warheads (the capabilities of which are not described but presumably are very powerful weapons, possibly nuclear). Her crew also encountered the Leoben Conoy Cylon model, posing as an arms trader, who eventually gave the Colonials their first discovery of humanoid Cylon infiltrators. Galactica is joined by a civilian convoy of survivors gathered by President Laura Roslin. When they arrive, then-Commander William Adama was persuaded to alter his original plan to send Galactica into a suicidal fight against the Cylons into one of exodus from the Colonies to save the last of humanity.
Galactica protected the civilian fleet as they made an FTL jumps from Ragnar towards the Promar Sector, well beyond the "Red Line" of charted space, never to return to the solar system of the Colonies in an effort to escape the Cylons. Soon after the battle, the Cylons dock at the station to retrieve the Cylon agent Aaron Doral, who was exiled at the station on the orders of Commander Saul Tigh.