Page:Star Lore Of All Ages, 1911.pdf/189

Rh Alpha Cassiopeiæ was known to the Arabs as "Schedar" or "Schedir," meaning "the Breast." Burritt tells us that Schedir is from "El Seder," the "Seder tree," a name given to the constellation by Ulugh Beg. Schedir was discovered to be a variable star by Birt in 1831. It culminates at 9 Nov 18th.

Beta Cassiopeiæ, or "Caph" an Arab title meaning "the Hand," was also known to the Arabs as "the Camel's Hump." It is one of the so-called "Three Guides," three stars that mark the equinoctial colure, one of the great circles passing through the poles of the heavens.

Caph is one of the stars for which a parallax has been found. It is approximately twenty light years from our system, though some authorities say thirty-two light years.

Gamma Cassiopeiæ, the second magnitude star in the girdle of the "lady in the chair," has a companion of the 11th magnitude 2″ distant. The Chinese called this star "a whip." It is a star of great interest to astronomers, as it was the first star discovered to contain bright lines in its spectrum. This discovery was made by Secchi in 1886. The spectrum is peculiarly variable.

Delta Cassiopeiæ bears the Arab name "Ruchbah," meaning "the Knee." It was utilised, says Allen, by Picard in France in 1669 in determining latitudes during his measure of an arc of the meridian, the first use of the telescope for geodetic purposes.

Theta and Mu Cassiopeiæ were known to the Arabs as "Al-Marfik," meaning "the Elbow." The star Mu is interesting because of its great proper motion. This is given as 3.7 seconds per year, a velocity in space of one hundred miles a second. It has been estimated that in 3,000,000 years this star will circle the heavens. It is said to be thirty light years distant.

Eta Cassiopeiæ is a double star, and one of the finest objects in the sky for a moderate sized telescope. It is probably the nearest star to us of any in the constellation, although authorities differ as to its parallax. This is given 9