Based on the principle of period transit method, semi-period transit method of collimation is proposed to improve the north-seeking speed and the automatic degree.
由陀螺仪寻北中天法的基本原理出发，提出了一种固定照准部的初寻北半周期中天法。
2
On Saturday evening he went 74 minutes without potting a ball, a period in which Shaun Murphy scored 517 points in going from 6-3 down to 8-6 up in their semi-final.