纬度

arcsin(x)

冬至日(h)

夏至日(h)

0˚

0

12

12

10˚

4˚24'

11.41

12.59

20˚

9˚6'

10.79

13.21

30˚

14˚33'

10.06

13.94

40˚

21˚24'

9.51

14.85

50˚

31˚12'

7.84

16.16

60˚

48˚53'

5.48

18.52

≥66.5˚

90˚

0

24