北斗星是古人心目中的历书和钟表

年、月、日、时，是人类生活、生产，生存最重要的时间概念。五、六千年以前科学推算的历法和钟表还没有产生以前，我国先民依靠对日月星辰运行规律的观测来确定年月日时等时间概念。北斗七星则是一部摆在天空的历书和时钟。凭着对北斗柄指向变化的观测，人们便可以精确得知春夏秋冬四季及其月、日和一日的具体时间。

Big Dipper,the almanac and clock in ancient' s minds

Year,month,day and hour are the most important time concept in the life,production and survival of mankind.Before the emerging of calendars and clocks five or six thousands years ago,our ancestors determined the time according to the operation rules of the sun,the moon and the stars.the Big Dippre was the calendar and clock in the sky,from which,people would know the accurate time of the year based on the direction pointed to by the handle of Big Dippre.