Part 12

It is claimed that Cepheus was known to the Chaldaeans twenty-three centuries before our era.

Surrounding , , , and , which mark the king's head, is a vacant space in the Milky Way, similar to the Coal Sack of Cygnus.

About 4 from , in the direction of is a pretty pair of sixth-magnitude stars.

Owing to precession, , , and Cephei will be successively the Pole Star in 4500, 6000, and 7500 A.D. respectively.

is a double whose components are yellow and blue. It is an interesting variable changing from magnitude 3.7 to 4.9 at intervals of 5 days 8 hours 47 minutes. As it is three times as bright at maximum as at minimum and can be observed with the naked eye its variations are well worth observing.

PEGASUS (peg'-a-sus)--THE WINGED HORSE. (Face South.)

LOCATION.--One corner of the Great Square is found by drawing a line from Polaris to Cassiopeia, and prolonging it an equal distance.

The Great Square is a stellar landmark. Three of the corners of the square are marked by stars in Pegasus; the fourth, and northeastern, corner is marked by the star Alpheratz in Andromeda. Each side of the square is about 18 long.

The horse is generally seen upside down, with his fore feet projected up into the sky. Only the head, neck, and fore feet are represented. The star Enif marks the nose.

is an interesting double, easily seen in an opera-glass. All the stars of the Square are approaching us at an inconceivable speed.

The position of the asterism Equus or Equ[=u]leus, the Little Horse, or Horse's Head, is shown in the diagram.

Delphinus, the water jar of Aquarius, and the circlet in the Western Fish, are all in the vicinity of Pegasus, and indicated in the diagram.

The winged horse is found on coins of Corinth 500 to 430 B.C. The Greeks called this constellation [Greek: hippos].

Pegasus seems to have been regarded in Phoenicia and Egypt as the sky emblem of a ship.

Within the area of the Square Argelander counted thirty naked-eye stars.

Note a fine pair in Equ[=u]leus just west of the star Enif in Pegasus.

The position of the equinoctial colure is defined by a line connecting Polaris, Cassiopeiae, Andromedae, and Pegasi.

ANDROMEDA (an-drom'-e-d[:a])--THE CHAINED LADY.

LOCATION.--The star Alpheratz is at the northeastern corner of the great square of Pegasus, one of the stellar landmarks.

Running east from , at almost equal distances, are four other stars, two of which are of the second magnitude. The most easterly one is Persei, known as Algol, the famous variable. Lines connecting the stars Andromedae, Algol, and 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 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 Nebulae." 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 Pegasi is the base. A line drawn from to Cassiopeiae and prolonged a little over twice its length points it out.

PERSEUS (per'-s[=u]s)--THE CHAMPION. (Face Northeast.)

LOCATION.-- Persei lies on a line drawn from to Andromedae, and is about 9 from the latter. The most striking feature in Perseus is the so-called "segment of Perseus," a curve of stars beginning about 12 below Cassiopeia, and curving toward Ursa Major. Note the famous variable Algol the Demon star. It represents the Medusa's head which Perseus holds in his hand. It varies from the second to the fourth magnitude in about three and one-half hours, and back again in the same time, after which it remains steadily brilliant for two and three-quarters days, when the same change recurs. Algenib and Algol form with Andromedae, a right-angled triangle.

Note a dull red star near Algol, and a pretty pair just above Algenib.