This telescope moves the sensor head across the surface, changing the actual angle of the observation. The big poles around it are what suspends the head over the surface. It has actually a huge angle of observation. According to WP, 60° in its small 200 m aperture and 26.4° in its 300m aperture.
Keep in mind that this is the the range of motion of the primary beam, not how large a patch of the sky is visible to the receivers.
FAST can also move it's "mirror," the shell has some huge number of triangular sections on wires, so it should be able to point even more than arecibo which has an immutable reflector. Both have adjustable focal points (sensor head) on wires like you describe.