These aren't film frames from The Empire Strikes Back, even while they look exactly like Rebel Alliance's Echo Base, ion cannon included. They are not on the icy surface of planet Hoth, but much nearer, in the Arctic circle.
Photographer Christian Houge took these beautiful pictures of a military base in the Arctic circle. The ion cannon is really a radome, a weatherproof dome that protects the radar antenna.
And those dishes waiting for Imperial AT-AT walkers are not going to fire anything. They are probably just microwave communication towers.