Introduction to Celestial Globes

This OER was designed by the OU Academy of the Lynx (oulynx.org) in conjunction with the "Galileo's World" (galileo.ou.edu) exhibition at the University of Oklahoma.

Introductory Celestial Globe Activity

The night sky looks like an upside-down bowl set on the horizon, but as it turns around during the night it is easy to think of it as a giant sphere. To think of the stars as bright points of light lying on the inside surface of a giant celestial sphere which rotates around us once a day explains the appearances of the sky with simplicity and elegance. With good reason this common-sense explanatory scheme was adopted by ancient astronomers, and it remains the most convenient way to learn observational astronomy today.

Any rotating sphere has two poles at each end of the axis of rotation, and an equator which cuts the sphere in half. The equator lies in a plane perpendicular to the axis of rotation.

With a celestial globe, identify the north and south celestial poles and the celestial equator.

Note that the constellations depicted on a celestial globe appear reversed, since you’re on the “outside looking in.” Look through and across a celestial globe to inspect the constellations as they appear from Earth.

A “great circle” cuts a sphere into two equal halves.  On a celestial globe, find 3 great circles:

1. Horizon, based on one’s location on the surface of the Earth.

2. Celestial equator, a projection of the Earth’s equator.

3. Ecliptic, or path of the Sun.

Experiment with these three circles on the celestial globe.

Further OER's for the Celestial Globe

Use the following OER's to further explore the Galileo's World exhibition.

• Galileo's World iPad Exhibit Guide, itunes.apple.com/us/book/galileos-world-exhibit-guide/id1032005948?mt=1.
• Galileo's World iTunes U Course, itunesu.itunes.apple.com/enroll/FDS-EYK-MRL.
• Galileo's World website, galileo.ou.edu.

Celestial Globe Educational Cluster

We want to create variations on this activity that connect the Celestial Globe to a variety of ages and situations. Use the following chart and hyperlinks to find the one to best fit your group.