II. Position of the New Moon

"The Sun must not catch up the moon, nor does the sun outstrip the day. Each one is travelling in an orbit with its own motion". Al Quran, Sura 36, verse 40

At new moon, the moon and sun are in conjuction. In other words, the moon and sun are in the same part of the sky and the angle between the observed moon and the sun is thus small. As a result of this, the new moon cannot be seen as long as the sun is in the sky because of glare from the latter : 20-24 hours after the time it passes nearest the sun is the earliest an untrained eye can expect to see the new moon and even then one will see it only for a short time after sunset. The period for sighting is very brief because the earth's rotation makes the moon appear to set following the sun (Fig.1). This is in contrast to the full moon phase whence the moon and sun are in apposition and the observer sees the moon rising in the east as the sun sets in the west

Fig. 1: Apparent motions of the moon and sun at conjunction due to the earth's rotation.

Fig. 2: Apparent motions of the moon and sun at opposition due to the earth's rotation.