Multiple choice study cards for reviewing the Celestial Sphere.

Users have the opportunity to adjust several variables in this simulation demonstrating the Ancient Greek's Two Sphere Universe theory.

An image of "The Four Corners of the World Supporting the Celestial Sphere", created by Jean-Baptiste Carpeaux in 1872 (Original plaster model, height 280 cm).

In this interactive tutorial students will learn what causes the seasons, diurnal cycles and how the constellations move through the sky. Learn we are able to see other planets and how astronomical events affected life on the Earth.

To those of us who live on earth, the most important astronomical object by far is the sun. This article explains how the motion of the sun through our sky cause day and night, the passage of the seasons, and earth's varied climates.

A description of the ancient astrolabes and how they worked. Provides information about definitions, collections, and also includes photos.

Nicolaus Copernicus (February 19, 1473 - May 24, 1543) was the first astronomer to formulate a scientifically based heliocentric cosmology that displaced the Earth from the center of the universe. His epochal book, De revolutionibus...