Perhaps the first feature of Orion that strikes the eye is the arrangement of the three nearly equal bright stars which form the Belt. Their Greek-letter names are Delta, Epsilon, and Zeta, and by these they are usually designated, but there is a great charm in their Arabic titles, which, in the same order, are Mintaka, “Belt”; Alnilam (from “String of Pearls”); and Alnitah, “Girdle.” It will be observed that all of these names have a similar signification, and probably each of them was originally employed to designate the whole row.[2]
The Belt is remarkable in another way—it points very nearly toward Sirius; it is like a glittering signboard indicating the position of the brightest star in the sky. To hasty observation the row seems to be perfectly straight, although there is in reality a slight bend, and the distances separating the three stars appear to be exactly equal. The effect is as beautiful as it is surprising.
Below the Belt hangs a fainter row of stars constituting the “Sword.” The central star of this row, Theta (θ), arrests the attention at once by a curious appearance of nebulosity, especially if it is examined with an opera-glass. A telescope shows it to be enveloped in one of the grandest nebulæ in the sky, the celebrated “Great Nebula of Orion.” With a large glass its appearance is astonishing in the highest degree. Instead of being elongated like the great nebula in Andromeda, it is about as broad as long, with no single centre of condensation, but many curdled accumulations, interspersed with partial gaps, and a great variety of curved lines of brighter nebulosity, suggesting the misty skeleton of some nondescript monster impact of phosphorescent clouds. A large number of stars are scattered over or through it, and some of them seem clearly to be connected with it, as if created out of its substance. Unlike the Andromeda nebula, this shows only the spectrum of glowing gas, so that no such supposition as has been made in the other case—viz., that it may be an outside universe—is admissible here. It is rather a chaos, rich with the elements from whose combinations spring suns and planets, and where the effects of organizing forces are just beginning to become manifest. It resembles a vast everglade filled with tangled vegetation and uncouth growths, but where the fertile soil, once cleared and drained, is capable of producing an enormous harvest.
On either side of the Belt, but far removed from it, shine the two great stars of Orion, Alpha (α), or Betelgeuse (from an Arabic phrase meaning the “Armpit of the Central One”), and Beta (β), or Rigel (from an Arabic phrase meaning the “Leg of the Giant”). These stars differ remarkably in color, Betelgeuse being orange-hued, and Rigel white. Although Betelgeuse takes precedence in the Greek-letter ranking, it is variable in brightness, sometimes exceeding Rigel in brilliance, and sometimes falling below it. The changes are uncertain in a long and as yet unascertained period. There is here an opportunity for an amateur to make valuable observations. But such observations must be continued over a considerable period of years.
Both stars are of immense actual magnitude. Their distance is so great that no trustworthy estimate of their parallax has yet been made. Rigel was put by Newcomb in his “XM” class, to which we have several times referred. It is without doubt one of the mightiest suns in the universe. It is also a double, and one of the finest in the sky. Close to its flaming rays the telescope reveals a small, intensely blue star. The distance is about 9″.5. In its general aspect Rigel resembles Vega, but the latter has a more decided blue tint. Scientific photometry gives the precedence in brightness to Vega, which is ranked as of magnitude 0.1, while Rigel is 0.3, which means that the first is one-tenth, and the second three-tenths of a magnitude below the 0 rank. It is very interesting to bring Rigel and Betelgeuse close together with a good sextant and then note the difference in their color.
The star Gamma (γ), or Bellatrix, the “Amazon” or “Female Warrior,” marks the left shoulder of the imaginary giant. Astrological superstition connects this star with the fortunes of women. Kappa (κ), or Saiph, “Sword” (although it is far from the Sword), is in the right knee of the figure. The head is marked by a little triangular group of stars, the chief of which is Lambda (λ), a fine double, yellow and purplish; distance 4″.5. The “lion’s hide” which Orion is represented as carrying on his left arm like a shield is shown by a bending row of small stars, beginning with Pi (π) and running upward between Bellatrix and Aldebaran in Taurus. The reader who is not provided with a telescope is advised, at least, to employ an opera-glass in sweeping over the whole space included in Orion. It is a region superb in its beauty and grandeur. Around the Belt, particularly, the sky is filled with sparkling multitudes infinitely varied in size, color, and grouping. As already said, this part of the firmament contains an enormous spiral nebula, which, although it can only be seen in photographs, seems to manifest its presence to the eye by the significant arrangement of small stars in curving lines. A word should be added about the star Zeta, or Alnitah, at the southeastern end of the Belt. It is a triple, very remarkable for the indescribable color of its second largest component. The Russian astronomer Struve could find nothing exactly resembling it in tone in the whole gamut of spectral colors, and he invented a special name to describe it—olivacea-sub-rubicunda, which may be translated “ruddy-olive.” It is 2″.5 from its larger companion. The third star is very faint, and distant 56″. When the telescope is directed to the star Sigma (σ) there comes into view an astonishing double group of stars, among which such colors as pale blue, “grape-red,” ruddy, and “gray” have been detected. The effect upon the mind of seeing such combinations of tinted suns transcends all power of description. With the feeling of pleasure that they give goes a sense of staggering wonder.
West of Orion, beginning near Rigel, is seen the constellation Eridanus, the River Po. Its stars are interesting for their plainly streaming tendency rather than for their individual peculiarities. Rising slightly from the neighborhood of Rigel, the stream runs in a graceful curve under Taurus, and continues westward until it meets Cetus, where it turns downward toward the horizon, and then sweeps back eastward again, disappearing behind the southern horizon below Orion and Lepus. It has no large star visible in northern latitudes, but in the southern hemisphere it contains one of the brightest stars in the sky, Achernar, the “End of the River.” All of the ancients saw a river in this part of the sky, a fact which does not surprise the observer when he has once noted the arrangement of the stars of Eridanus. Its stars are so numerous that the old uranographers seem to have grown weary of attaching letters to them; or rather, perhaps, the alphabet was too short to answer the demand, for no less than nine of them, beginning from the one thus lettered in [Chart V], are called Tau (τ), as τ¹, τ², τ³, etc. (For the origin of the association of Eridanus with the River Po, and with the story of Phaeton, see Astronomy with the Naked Eye).
The constellation Lepus, the Hare, below Orion, and marking the place where Eridanus turns finally to flow into the far south, is noteworthy only for its groupings of stars. It contains one star too faint to be seen with the naked eye near the western border of the constellation, below and to the right of the little group under Rigel, in [Chart V], which is so intensely crimson that Hind likened its appearance to a blood drop.
We turn next to Taurus. On account of the beauty of Aldebaran and the Pleiades, this constellation hardly falls behind Orion in attractiveness. Aldebaran (Arabic Al Dabaran, the “Follower”) is the chief star of the constellation and the leader of the group called the Hyades, a name which Lewis derives from the Greek word ὕειυ, to rain, because their rising was connected with the beginning of the rainy season. Popularly the group is known as the “Letter A,” whose form it imitates, although it is usually seen nearly upside down. The letter V would perhaps better represent our view of it. It is a glorious sight with an opera-glass. Aldebaran is distinctly red, but of a peculiar tone, which has frequently been called rose-red. Its redness is certainly unlike the orange tone of Betelgeuse. When gazing at it in a fanciful mood, I have often likened it imaginatively to an apple-blossom in color. Flammarion has translated the Hebrew name of this star, Aleph, as “God’s Eye.” Taurus, he says, is the most ancient of the signs of the zodiac, the first that the Precession of the Equinoxes placed at the head of the signs, and he adds that observational astronomy appears to have been founded at the epoch when the Vernal Equinox lay close to Aldebaran—i. e., about three thousand years before the commencement of our era.
The beauty of Aldebaran, the singularity of the figure shaped by its attendants, the charming effect produced by the flocks of little stars, the Deltas and the Thetas, in the middle of the arms of the letter, and the richness of the stellar groundwork of the cluster, all combine to make the Hyades one of the most memorable objects in the sky; but no one can describe it, because the starry heavens cannot be put into words. Terrestrial analogies, and phrases applied to things seen on the earth, utterly fail to convey the impressions made by such spectacles. I can only again urge the reader to examine the Hyades with a good opera-glass on a clear night when there is no moonlight to interfere. Some one once said, “If you would test your appreciation of poetry, read Milton’s Lycidas”; so I would say, If you would know how you are affected by nature’s masterpieces in the sky, look at the Hyades.