A: Observed without a telescope, the sky appears essentially fixed and unmoving. Viewed through even a small telescope, however, the situation is quite different. Although the sky (the "celestial sphere" containing all the stars, planets, and other objects) is, in fact, essentially fixed, the Earth turns underneath the sky once every 24 hours.

This motion is magnified by the telescope, to the point where astronomical objects appear to move through the telescope's field of view in 10 to 30 seconds. It is therefore important for the observer to be able to follow, or track, objects as they move through the field.

Meade telescope models provide several different means of accomplishing this tracking requirement, from the manual tracking controls of the Model NG-60, for example, to the computerized tracking of the LX200GPS series.

What are Right Ascension and Declination?

A: Analogous to the Earth's longitude and latitude, the celestial sphere is divided by a grid of lines that are used to define the positions of every object in the sky. Just as the location of, say, New York City, is defined on Earth by its longitude and latitude, so the position of the Orion Nebula in the sky is defined by its Right Ascension and Declination. Right Ascension is the celestial analog to the Earth's longitude, and Declination is the celestial analog to the Earth's latitude.