sasuke said:

How could the supergiant military station of 180 km diameter reduce to dust a cosmic body that is hundredfold the station itself?

E = m c^2

Converting even a small fraction of its mass into energy would be sufficient.

Ok, let's assume I accepted this explanation. But some inconsistency still left: in James Kahn novelization the Emperor gives the instruction to DS 2 chief commander in case the rebels destroy the shield to blast Endor turning DS to it. And this looked quite utopian because if DS 2 managed somehow to destroy the giant planet then DS itself together with the Emperor would be cindered with the enormous hit of detonated body, wouldn't it?