Page:Star Lore Of All Ages, 1911.pdf/62

26 aked eye appearance. It is an enormous body, estimated to be in length as much as thirty thousand times the distance of the earth from the sun (ninety-three million miles), a proportion inconceivable. Herschel thought that the nebula was resolvable into separate stars, although his glass failed to prove the fact. Later observations with more powerful telescopes confirmed his opinion. An examination made at Cambridge in 1848 proved the existence of upwards of fifteen hundred minute stars within the nebula, while the nebulous character of the whole was still apparent. In the spectroscope this nebula gives clearly a continuous spectrum, thus proving that it is not a mass of incandescent gas but rather a highly condensed cluster of stars. Recent and more reliable calculations of its distance give it a light journey of about nineteen years.

The star Alpha Andromedæ, or Alpheratz as it was called by the Arabs, was formerly associated with the constellation Pegasus, and called Delta Pegasi. The Arabs also knew this star as "Sirrah," and it represented to them the horse's navel. Alpheratz is situated at the north-eastern corner of the Great Square of Pegasus, a stellar landmark, and is known as one of the "Three Guides," marking the equinoctial colure, the prime meridian of the heavens, Beta Cassiopeiæ and Gamma Pegasi being the other two guides. In astrology Alpheratz portended honour and riches to all born under its influence. It culminates at 9, on the 10th of November. Alpheratz is situated in the head of the figure of Andromeda, and was familiarly known as "Andromeda's Head" in England two centuries ago. In all late Arabian astronomy taken from Ptolemy it was described as the "Head of the Woman in Chains." According to Prof. Russell, Alpheratz has a dark companion spectroscopically revealed, revolving about it in a