Page:Star Lore Of All Ages, 1911.pdf/205

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Cetus, the Whale
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few telescopic objects of interest. The south pole of the Milky Way is located within its borders, and the constellation "is a condensation point of nebulæ, directly across the sphere from Virgo, also noted in this respect."

Alpha Ceti is no longer the lucida of the constellation, as its Greek-letter name would indicate, for it is inferior in brightness to Beta. One or both of these stars have therefore changed in the course of time. Alpha is well worth observing as a fine combination of a beautiful 2.5 magnitude orange-coloured star with a 5.5 magnitude star of a decided bluish tint. The Arab name for Alpha is "Menkar," meaning "the nose." λ Ceti also bears this name, and as it is situated exactly in the nose of the creature it seems more appropriately named than Alpha. Astrologically Menkar denoted sickness, disgrace, and ill fortune, with danger from great beasts.

β Ceti was known to the Arabs as "Diphda" or "Deneb Kaitos." Diphda signifies "the Frog," and this star was called "the Second Frog," the first one being represented by the star Fomalhaut situated in the mouth of the Southern Fish. The name "Deneb Kaitos" means "the Tail of the Whale toward the South." In China this star bore the strange title of "Superintendent of Earthworks."

No account of the constellation Cetus would be complete without a reference to the wonderful variable star Mira, or Omicron Ceti as it is generally called by astronomers. Historically it is the most interesting of all the variable stars of long period, and it bears the distinction of being the first star whose variability was discovered.

D. Fabricius observed it early on the morning of the I2th of August, 1596, as somewhat brighter than α Arietis. In October it had disappeared. He observed it again in February and March, 1609. Holwarda observed it in 1638, and recognised its periodical variability.

According to Argelander's calculations its period is 331½ days, but it is very irregular, and the difference of period is sometimes as much as twenty-five days. Its

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