Table 4
Eigenfrequencies of the telescope structure.
Mode | fi [Hz] | Shape description |
---|---|---|
#1 | 1.8 | M2 twist about LOS on quadripod |
#2 | 1.9 | ERS longitudinal w.r.t. the ARS |
#3 | 2.1 | ERS lateral w.r.t. the ARS |
#4 | 3.0 | Full telescope on track rotation about AZ |
#5 | 3.1 | Lateral bending for Nasmyth instr. |
Notes. Results of the modal analysis to determine the eigenfrequencies of the antenna structure. The first five frequencies, fi , where i = 1,2, 3,4,5, and descriptions of the mode shapes are listed for EL = 90°. Mode #5 describes the lateral bending of the Nasmyth support platform due to the mass and inertia of the Nasmyth instrument. Here, LOS stands for line of sight, ARS stands for azimuthal rotating structure, and ERS stands for elevation rotating structure.
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