The Gold Cluster, sometimes referred to as the "Star Cluster", is the Colonials' highest battle award.
Sire Uri and the Quorum organize a gathering to give this decoration to Apollo, Starbuck, and Boomer for their roles in clearing the Straits of Madagon for the Fleet, allowing them to make it to Carillon in time to resupply. The award is, in part, a political move on Uri's part to attempt to mollify Adama. Uri plans on asking for the disarmament of the Fleet at the award ceremony, hoping that doing so would pacify the aggression of the Cylons (TOS: "Saga of a Star World").
After Major Sheba's assault force slays Major Boomer's assailant, Chief Paris, aboard Hephaestus, Sheba jokes that he wouldn't be awarded "the Golden Cluster if you don't get shot at least once" (RH: Armageddon).