The sun passes through this point every December solstice
and has been doing this for the last 50 years or so," says ROM astronomy educator Ian McGregor.
At the June solstice, the Sun reaches its highest position above the northern side of the rings, at the December solstice
it reaches its highest position above the southern side.
The perpendicular rays of the sun "move" northward, reaching perpendicular at the Tropic of Cancer (23 1/2[degrees] N latitude) in the northern hemisphere on the June solstice and reach perpendicular at the Tropic of Capricorn (23 1/2[degrees] S latitude) in the southern hemisphere on the December solstice
Ghezzi decided to use modern-day science to test out this theory, and to his delight, he discovered that the first tower aligned with the June solstice and the last tower with the December solstice
that our first sources, Betanzos (1551) and Polo (1559), emphatically state that the Inca year began with its most important month of 'December', referring to the Inca month before the December solstice