Bastion Class Orbital Weapons Platform image - Sins of the Sirius Sector mod for Sins of a Solar Empire: Rebellion

The Bastion Class is derived from the modular Bulwark Orbital Platform which was originally developed to intercept debris from falling into a planets atmosphere.
The Weapons Platform is heavily armored and able to take most battleships one-on-one. The Plasma Cannon Turrets are very powerful if a bit short ranged and while they are quite capable of turning larger craft into slag the lack the mobility to track most fighter craft.