Page:Popular Science Monthly Volume 47.djvu/804

786 scope is able to show it, and all our knowledge about it is based upon photographs. It might be supposed that it was a nebulous disk seen edgewise, but for the fact that at the largest star involved in its course it bends sharply about 10º out of its former direction, and for the additional fact that it seems to take its origin from a curved offshoot of the intricate nebulous mass surrounding Maia. Exactly at the point where this curve is transformed into a straight line shines a small star! In view of all the facts the idea would not seem to be very far-fetched that in the Pleiades we behold an assemblage of suns, large and small, formed by the gradual condensation of a nebula, and in which evolution has gone on far beyond the stage represented by the Orion nebula, where also a group of stars may be in process of formation out of nebulous matter. If we look a little farther along this line of development, we may perceive in such a stellar assemblage as the cluster in Hercules, a still later phase wherein all the originally scattered material has, perhaps, been absorbed into the starry nuclei.

The yellow star Σ 430 has two companions: magnitudes six, nine, and nine and a half, distances 26″, p. 55°, and 39″, p. 302°. The star 30 of the fifth magnitude has a companion of the ninth magnitude, distance 9″, p. 58°, colors emerald and purple, faint. An interesting variable, of the type of Algol, is λ, which at maximum is of magnitude three and four tenths and at minimum of magnitude four and two tenths. Its period from one maximum to the next is about three days and twenty-three hours, but the actual changes occupy only about ten hours, and it loses light more swiftly than it regains it. A combination of red and blue is presented by φ, (mistakenly marked on map No. 23 as ψ. The magnitudes are six and eight, distance 56″, p. 242°. A double of similar magnitudes is χ, distance 19″, p. 25°. Between the two stars which the naked eye sees in κ is a minute pair, each of less than the eleventh magnitude, distance 5″, p. 324°. Another naked-eye double is formed by θ1, and a θ2, in the Hyades. The magnitudes are five and five and a half, distance about 5' 37″.

The leading star of Taurus, Aldebaran (α), is celebrated for its reddish color. The precise hue is rather uncertain, but Aldebaran is not orange as Betelgeuse in Orion is, and no correct eye can for an instant confuse the colors of these two stars, although many persons seem to be unable to detect the very plain difference between them in this respect. Aldebaran has been called "rose-red," and it would be an interesting occupation for an amateur to determine, with the aid of some proper color scale, the precise hue of this star, and of the many other stars which exhibit chromatic idiosyncrasy. Aldebaran is further interesting