دراسة تغيرات مدة الشفق الفمكي في العراق خالل سنة 2008 م

Abstract

Twilight is the illumination in the horizon before sunrise and after sun set, in this paper the variation of Astronomical twilight time was calculated for three Iraqi main cities (Baghdad, Mousal and Basra) for 2008. It’s was found there is difference in twilight time between the three cities, the variation between Baghdad and Mousal was (3-7)min, between Baghdad and Basra was (3-6)min and between Mousal and Basra was (6-14)min. Also it was found that difference between maxim and minimum twilight was (26)min for Baghdad, Mousal was(31)min, and Basra was (23)min. This difference it was Proved the reference criteria which give (90) min for twilight time after sunset is not correct.