弧秒的英文怎么说
弧秒的英文: One second of arc movement is one thirtieth of a millimetre. If the diameter of the pupil is 6 mm the eye is able to separate 120 seconds of arc Until recent years, this tilt has increased by around 6 arc seconds, or about one-fifth of a millimetre each year n. 反正割函数 |