http://www.astronomy.org/programs/se...flashlight.gif

The tendency to see variable axial tilt into and out of the solar
radiation/orbital shadow boundary is perhaps the greatest
disappointment in a long line of poor conceptual notions of the
Earth's dual motions.

Successful people do not do this,they would not ignore that the
dynamic which generates global climate and hemispherical weather
patterns is due to the alteration in the Solar radiation/Orbital
shadow boundary against fixed rotational orientation.

The standard graphic above, based on the pseudo-dynamic of variable
axial tilt, looks fine until a person tries to discern what moves in
order for the solar radiation/orbital shadow boundary line up with the
rotational axis at the Equinoxes.I urge responsible people to try and
rectify the situation where variable inclination,first proposed by
Copernicus, needs to be modified to reflect 21st century data and
concerns.


"To this circle, which goes through the middle of the signs, and to
its plane, the equator and the earth's axis must be understood to have
a variable inclination. For if they stayed at a constant angle, and
were affected exclusively by the motion of the center, no inequality
of days and nights would be observed. On the contrary, it would always
be either the longest or shortest day or the day of equal daylight and
darkness, or summer or winter, or whatever the character of the
season, it would remain identical and unchanged. " Copernicus Chapter
11

http://webexhibits.org/calendars/yea...opernicus.html

The modification is not to express hemispherical daylight/darkness
asymmetry and meteorological weather patterns astronomically but
rather to consider the alteration of the global SR/OS boundary against
rotational orientation astronomically and only then split it into
hemispherical differences .