THE CRESCENT MOON VISIBILITY RELEVANT TO SYNODICAL HALF MONTH’S

Abstract

The modern astronomic programs were development to calculate the sun and moon coordinates, moon phases (new moon and full moon), synodical half months and difference between them and time of synodical month and elongation angle from the sun at the moment of inception. Calculations were conducted for the years 2005-2010.The relation between crescent visibility and synodical half month period was studied (date of full moon –date of inception) relying on its change with sun –earth –moon angle(Elong) at synodic moment. The period when crescent presents synodical half month and its relation to new born crescent deviation angle from perigee(Mo) and node(F) .It was found out that crescent did not present synodical mid-period time. Synodical month period change and perigee and node movement were calculated