Document Type : Research Paper
Authors
1 Anbar University - College of Education and Pure Sciences
2 Baghdad University - College of Science, ,
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