| 摘要 |
Two pyrheliometers each carry out periodic scanning in a plane at right angles to one of the two perpendicular axes of pivotal displacement of the solar pointer. Each pyrheliometer is associated with means for measuring the angular difference between the direction of the sun projected on the scanning plane and the direction of the pointing axis projected on the same plane and for delivering a pointing error signal which is proportional to the angular difference. The error signal obtained in each scanning plane is applied to a motor for the pivotal displacement of the pointer so that the pointing axis is directed towards the sun when both error signals have been cancelled. |
