Dark Moon Astronomy

Astronomical information on the Dark Moon (source, wiki):

Dark moon is the period when the Moon appears so close to the Sun in the sky that it cannot be seen even near sunset or sunrise. Depending on how close the Moon passes to the line between Earth and Sun, dark moon may last between 1.5 to 3.5 days. The astronomical new moon occurs in the middle of this period when the Moon and Sun are in conjunction, and is also referred to as dark moon to distinguish it from the traditional new moon, which is the moment when the crescent moon is first seen one or two days after conjunction.