Fig. 4From: Absolute calibration of brightness temperature of the Venus disk observed by the Longwave Infrared Camera onboard AkatsukiOrientation of LIR aperture and solar incident angle between the direction to the sun and the -x-axis of the spacecraft. The spacecraft basically orients its the -x-plane toward Venus except when it communicates with the ground station on the Earth (Nakamura et al. 2007). The solar incident angle at observation depends on the orbit geometryBack to article page