This web page, authored and curated by David P. Stern, describes the precession of the Earth's axis of rotation relative to the stars. It describes the discovery by the Greek astronomer Hipparchus that the position of...

This is a diagnostic test developed by the Collaboration for Astronomy Education Research (CAER) for astronomy teachers teaching non-science majors at the introductory level. The first twenty one questions are content...

An algebra-based overview of elementary and pre-telescope astronomy. Topics covered include sundials, seasons, calendars, precession, shape and rotation of Earth, Greek astronomy, the path to heliocentric theory and...

Created by David P. Stern, this set of three web pages provides a calculation of paths, times, and distances for a flight to Mars and back. The author uses a Hohmann transfer ellipse between two circular orbits. This is...

Authored and curated by David P. Stern, these pages explore orbits and the "Lagrangian points", where objects will orbit the sun with the same period as the earth. This has applications for solar monitoring spacecraft....

Authored by Eleanor Kopsian of Franklin Frazier, this is an activity intended to help students understand orbital motion and Kepler's Laws through a comparison of a circle and an ellipse and the application of Kepler's...

This applet shows from three different physical perspectives the orbit of a low-mass test particle around a non-rotating black hole. Below the applet is an instructional guide to the applet and a description of the...