| 摘要 |
PURPOSE:To widen the detection range, to raise the detection sensitivity, and to execute a precise control by detecting the direction by using two pieces of optical fibers whose execs of tip parts have been inclined in the positive and negative directions against the incident direction, respectively, as a pair of photodetecting means. CONSTITUTION:Tip parts 32b, 34b of a pair of optical fibers 32, 34 are inclined by 30 deg. to positive and negative against the center axis CL, and incident light beams are led in from the respective end faces 32a, 34a, and made incident on photoelectric converting elements 40, 42. Output electric signals of the elements 40, 42 are amplified, respectively, and thereafter, applied to a differential amplifier 45 and an adder 46. The amplifier 45 applies a signal D being proportional to a difference of two input signals, to comparators 47, 48. The comparator 47 outputs '1' at the time of D>VHT (set value), and the comparator 48 outputs '1' at the time of D<TLT (set value). The adder 46 adds two input signals and generates an output S, and provides it to a comparator 49, and the comparator 49 outputs '1' at the time of S>VT (set value). Accordingly, an AND gate 50 outputs '1' at the time of D>VHT and S>VT, and an AND gate 51 outputs '1' at the time of D<VLT and S>VT, and they become control signals for moving an equatorial telescope in the positive and negative directions. |
