The Moon
(around 135º), the Moon reaches a point of least
blockage, a point where the most amount of solar
radiation can penetrate and reach the earth.
It is at this point in the lunar Second Quarter, the point
during which the greatest amount of radiation is
available to the earth, that the Eastern astrologers have
set aside as a time for the masculine (active) element.
The Fourth Quarter, where the Moon effectively blocks
the solar radiation, is the point at which the feminine
energies are most observed.
It is interesting that—on the surface at any rate—ancient
tradition and modern science appear to be in general
agreement.
Exoteric References
B. Bell and R.J. Defouw. 1966. Dependence of the lunar
modulation of geomagnetic activity on the celestial
latitude of the moon, J. Geophys. Res. 71: 951 - 957.