Location.—The star α Alpheratz is at the northeastern corner of the great square of Pegasus, one of the stellar landmarks.
Running east from α, at almost equal distances, are four other stars, two of which are of the second magnitude. The most easterly one is β Persei, known as Algol, the famous variable. Lines connecting the stars γ Andromedæ, Algol, and α Persei form a right-angled triangle. The right angle is marked by Algol.
The chief object of interest in this constellation is the great nebula, the first to be discovered. It can be seen by the naked eye and it is a fine sight in an opera-glass. Its location is indicated in the diagram.
The star γ is the radiant point of the Bielid meteors, looked for in November. It is a colored double visible in a 3" glass.
The great nebula has been called the "Queen of the Nebulæ." It is said to have been known as far back as a.d. 905, and it was described 986 a.d. as the "Little Cloud."
Andromeda is very favorable for observation in September, low in the eastern sky.
Note the characteristic "Y" shaped asterism known as Gloria Frederika or Frederik's Glory. It lies about at the apex of a nearly isosceles triangle of which a line connecting Alpheratz and β Pegasi is the base. A line drawn from δ to α Cassiopeiæ and prolonged a little over twice its length points it out.