There is an error in the formula for Substyle Distance in the original posting. I transcribed from my rough notes incorrectly. The correct formula, from Waugh, is Tan SD = Sin Dec / Tan Lat. With the latitude of 20.666 and wall declination of 18 this solves to the angle I quoted, 39.32 degrees.
The corrected URL is <http://www.piramideinn.com/equinox.htm>. Be patient as this server is often busy. There are some good pictures showing the equinox serpent at <http://web.kyoto-inet.or.jp/org/orion/eng/hst/maya/chichen1.html> The serpent is formed from shadows of the corners of the pyramid cast onto the vertical edge of the staircase. Roger Bailey 51 N 115 W At 07:56 AM 1/22/00 -0600, Warren Thom wrote: >Hi Roger, > >The Mayan pyramid sounds interesting. Thanks for posting. I had a problem >with the link in your message. I did find the following: > ><http://www.mont-acad.pvt.k12.al.us/projects/civ/beau/temp.html> > >I am still trying to picture how the "snake" image is produced. You did give a >good account. > >Warren Thom > >
