Astronomy for Astrologers
The polar axis of the Earth is in line with a vertical
light ray from the Sun only twice a year—at the summer
solstice and at the winter solstice.
At the equinoctial points (occurring in the Spring and
Fall) the polar axis of the Earth is at right-angles, or
'square', to a vertical light ray coming from the Sun.
At all other times of the year—times besides those
marked by these four cardinal points—the angle
between the polar axis of the Earth and a vertical light
ray coming from the Sun will be somewhere between 0°
and 90°. This angle gradually and constantly changes
through all time.