Can an Astronomical New Moon Be Seen by “Earthshine?
” Some calendar systems use an astronomical new moon or conjunction to begin each month. This event occurs when the moon is closest to the straight line between centers of the Earth and Sun. Today, this event is possible to calculate mathematically with a high degree of precision. Historical evidence indicates that this calculation could not be performed until about 330 BC. “The months beginning with the conjunction will be called exact lunar months or conjunction months. These months are a theoretical construction; they could not be used in practice in classical times, because before Kallippos (330 B.C.) astronomers were not able to predict the true conjunction.” (B.L. van der Waerden, The Journal of Hellenic Studies, vol 80, 1960, p. 169, “Greek Astronmical Calendars and Their Relation to the Athenian Civil Calendar”). There can be up to three successive nights between the last old crescent and the first new crescent (see reference, above). Without the ability to calculate the true c
