A good summary of observations and their impact on the geocentric and heliocentric models can be found at;

http://www.chabotcollege.edu/faculty/shildreth/astronomy/geoanswers.html.

There is also a good animation of the retrograde motion of Mars online at;

http://www.astro.utoronto.ca/~zhu/ast210/both.html.

Students' suggestions for good diagrams to support classroom notes on stellar evolution can be found at the following locations;

http://www.universetoday.com/18847/life-of-the-sun/

http://chandra.harvard.edu/edu/formal/stellar_ev/

(see the Interactive Guide to Stellar Evolution - available in both Flash and PDF versions)

Created by the Science Department of Grainville School, Jersey.