Page:Astronomy for Everybody.djvu/331

At 0 hours sidereal time the equinoctial colure is on the meridian; at six hours, the solstitial colure, and so on.

With this preliminary explanation let us proceed to the study of the constellations. I assume the reader to be somewhere in the latitude of the United States. Then the principal northern constellations will never set, and will be visible in whole or in part every evening in the year. With them, therefore, we begin.

A figure, showing these constellations, is found in the first part of the present book (Fig. 2). To see how they will appear hold the cut with the month at top; we then have the position at eight o'clock in the evening. For a later hour turn it a little in the direction of the arrows. For example, in July, at ten o'clock, we hold it so as to have August at the top.
Fig. 50.—Ursa Major, or The Dipper. The Roman numerals on top give the sidereal time without the trouble of calculating it.

First find Ursa Major, the Great Bear, generally called the Dipper, an implement which the constellation resembles much more than it does a bear. This you can always do except perhaps in autumn when, if you are far south, it may be more or less below the northern horizon. Notice the pair of stars forming the outside