Describes the effects of various astronomical and terrestrial phenomena on sightibility of the new moon; namely; visibility altitudes of the moon; elongation; ecceutricity of moon’s; orbit and advance of apsides; regression of nodes; latitude; height of the observer and depression of the sun. A diagram is devised (based on mathematical relation) to give directly the value of the function f(c,a) (apparent brightness of the moon) for any elongation of the moon between 5 to 40 degrees, and for any altitude.