Wind induced surface deformation of the Nobeyama 45-m radio telescope

Reflector surface deformation due to wind loading on the Nobeyama 45-m antenna has been measured with four LED lamps on the surface at r = 20 m and two CCD cameras on the central hub as it rotates in azimuth with elevation angles of 90 and 11 degrees. The side-wind loading of 8.4 m s -1 caused a tilt of 12 arcseconds and an astigmatic deformation of 0.8 mm. The front- and back-wind loading of 9.9 m s -1 induced a vertical displacement variation of 2.3 mm. These largescale surface deformation profiles have been compared with those of finite element calculations and coefficients of axial force and yaw moment predicted by a JPL wind tunnel data excerpt.