Which "natural cycles" define the Satanic Holidays?

[magnum.arcanum]

I'm referring to the website description.  Their is the chart of the moon cycle.  The planetary cycle effects the moon cycle, as does astral manifestation and the associated alignments.  When we say that the Satanic Holidays are defined by the "natural cycles", which cycles?  Is it simple like the moon phases or is it more nebulous like large-scale Astrological alignments and their effect on the astral?