This puts the angular size of the Star Destroyer at 0.75° at a distance of 221 kilometers. That's actually pretty low altitude since the view is closer to the horizon and not directly overhead.

THE existence of a source in the Crab Nebula with an angular diameter of less than 1 sec of arc has been revealed by observations of interplanetary scintillation at a frequency of 38 Mc/s (ref. 1 ...