Page:Popular Science Monthly Volume 46.djvu/769

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749
PLEASURES OF THE TELESCOPE.

has a comparatively small orbit, and its components are never seen widely separated. In 1826 their distance was 0·7″; in 1880 they conld not be split; in 1891 the distance had increased to 0·36″, and in 1894 it had become 0·53″, p. 123°. The period has been estimated at one hundred years.

While the group of double stars in the southern part of Corona Borealis consists, as we have seen, of remarkably close binaries, another group in the northern part of the same constellation comprises stars that are easily separated. Let us first try ζ. The powers of the three-inch are amply sufficient in this case. The magnitudes are four and five, distance 6·3″, p. 300°. Colors, white or bluish-white and blue or green.

Next take σ, whose magnitudes are five and six, distance 4″, p. 200°. With the five-inch we may look for a second companion of the tenth magnitude, distance 54″, p. 88°. It is thought highly probable that σ is a binary, but its period has simply been guessed at.

Finally, we come to ν, which consists of two very widely separated stars, ν1 and ν2, each of which has a faint companion. With the five-inch we may be able to see the companion of v2, the more southerly of the pair. The magnitude of the companion is variously given as tenth and twelfth, distance 137″, p. 18°.

With the aid of the map we find the position of the new star of 1866, which is famous as the first so-called temporary star to which spectroscopic analysis was applied. When first noticed, on May 12, 1866, this star was of the second magnitude, fully equaling in brilliancy α, the brightest star of the constellation; but in about two weeks it fell to the ninth magnitude. Huggins and Miller eagerly studied the star with the spectroscope, and their results were received with the deepest interest. They concluded that the light of the new star had two different sources, each giving a spectrum peculiar to itself. One of the spectra had dark lines and the other bright lines. It will be remembered that a similar peculiarity was exhibited by the new star in Auriga in 1893. But the star in Corona did not disappear. It diminished to magnitude nine and a half or ten, and stopped there; and it is still visible. In fact, subsequent examination proved that it had been catalogued at Bonn as a star of magnitude nine and a half in 1855. Consequently this "blaze star" of 1866 will bear watching in its decrepitude. Nobody knows but that it may blaze again. Perhaps it is a sunlike body; perhaps it bears little resemblance to a sun as we understand such a thing. But whatever it may be, it is there, and it has proved itself capable of doing very extraordinary things.

We have no reason to suspect the sun of any latent eccentricities like those that have been displayed by "temporary" stars; yet, acting on the principle which led the old emperor-astrologer