Active Surface Compensation for Large Radio Telescope Antennas

Table 4

Four radio telescopes with active main surface.

Name	Forms of main reflectors	Surface accuracy (mm)	Number of blocks	Types of panels	Shapes of panels	Manufacturing accuracy of single panel (μm)	Number of actuators
GBT	Offset Gregorian	0.24	2004	44 rings	Trapezoid	68	2209
LMT	Standard Cassegrain	0.075	180	5 rings	Irregular quadrilateral (combination)	<40	720
SRT	Shaped Gregorian	0.15	1008	14 rings	Trapezoid	<65	1116
Tianma	Shaped Cassegrain	0.3	1008	14 rings	Trapezoid	<130	1104