At Cape Laplace at 9:22 p.m. May 23, 2010, the Sun would have appeared to be at some angle above its local horizon. The angle from the sub-solar point to the top of the cape can be used to find the Sun's altitude that, combined with the height of the cape, caused the shadow.
The Sun's altitude can be simply calculated by subtracting the angle from the sub -solar point to the top of the cape from 90 degrees:
Asun = 90o - gtop
The value should be at or near:
Asun = 6o.7010508
6 - The Sun Altitude was Last Updated on December 06, 2010