This brilliant northern constellation, composed, with the exception of δ, of stars of the second magnitude, has frequently been celebrated by poets. We may paraphrase, for the advantage of our readers, a glowing apostrophe from the pen of the American Ware:—
With what grand and majestic steps, he says, it moves forward in its eternal circle, following among the stars its regal way in a slow and silent splendour! Mighty creation, I salute thee! I love to see thee wandering in the shining paths like a giant proud of his strong girdle—severe, indefatigable, resolved—whose feet never lag in the road which lies before them. Other tribes abandon their nocturnal course and rest their weary orbs under the waves; but thou, thou never closest thy burning eyes, and never suspendest thy determined steps. Forward, ever forward! While systems change, and suns retire, and worlds fall to sleep and awake again, thou pursuest thy endless march. The near horizon attempts to check thee, but in vain. A watchful sentinel, thou never quittest thy age-long duty; but, without allowing thyself to be surprised by sleep, thou guardest the fixed light of the universe, and preventest the north from ever forgetting its place.
Seven stars dwell in that shining company; the eye embraces them all at a single glance; their distances from one another, however, are not less than the distance of each from Earth. And this again is the reciprocal distance of the celestial centres or foci. From depths of heaven, unexplored by thought, the piercing rays dart across the void, revealing to our senses innumerable worlds and systems. Let us arm our vision with the telescope, and let us survey the firmament. The skies open wide; a shower of sparkling fires descends upon our head; the stars close up their ranks, are condensed in regions so remote that their swift rays (swifter than aught else in creation) must travel for centuries before they can reach our Earth. Earth, sun, and ye constellations, what are ye among this infinite immensity and the multitude of the Divine works!
If we face towards the Pole-Star, which, as we have seen, preserves its place in the centre of the northern region of the sky, we have the south behind us, the east is on our right, the west upon our left. All the stars revolving round the Pole-Star, from right to left, should be recognized according to their mutual relations rather than referred to the cardinal points. On the other side of Polaris, as compared with the Great Bear, we find another constellation which is easily recognized. If from the central star δ we carry a line to the Pole, and then prolong it for an equal distance, we traverse the constellation of Cassiopeia, composed of five stars of the third magnitude, disposed somewhat like the outer jambs of the letter M. The small star χ, terminating the square, gives it also the form of a chair. This group occupies every possible situation in revolving round the Pole, being at one time above it, at another below, now on the left, and then on the right; but it is always readily found, because, like Ursa Major, to which it is invariably opposite, it never sets. The Pole-Star is the axle round which these two constellations revolve.
If we now draw, from the stars α and δ in Ursa Major, two lines meeting at the Pole, and afterwards extend them beyond Cassiopeia, they will abut on the square of Pegasus, which is bounded on one of its sides by a group, or series, of three stars resembling the triangle in Ursa Major. These three belong to the constellation of Andromeda (α, β, and γ), and themselves abut on another three-orbed group, that of Perseus.
The last star in the square of Perseus is also the first α of Andromeda: the other three are named, Algenib, γ; Markab, α; and Scheat, β. To the north of Andromeda β, and near a small star, ν, the Arctic traveller will discern an oblong nebula, which may be compared to the light of a taper seen through a sheet of horn; this is the first nebula to which any allusion occurs in the annals of astronomy. In Perseus α, an orb of great brilliancy, on the prolonged plane of the three principal stars of Andromeda, shines with steady lustre between two less dazzling spheres, and forms in conjunction with them a concave arc very easily distinguished. Of this arc we may avail ourselves as a new point of departure. By prolonging it in the direction of δ, we come to a very bright star of the first magnitude, the Goat. By forming a right angle to this prolongation in a southerly direction we come to that glorious mass of stars, not very frequently above the Polar horizon, the Pleiads. These were held in evil repute among the ancients. Their appearance was supposed to be ominous of violent storms, and Valerius Flaccus speaks of them as fatal to ships.
NEBULA IN ANDROMEDA.
Algol, or Medusa’s Head, known to astronomers as Perseus β, belongs to the singular class of Variable Stars. Instead of shining with a constant lustre, like other orbs, it is sometimes very brilliant, and sometimes very pale; passing, apparently, from the second to the fourth magnitude. According to Goodricke, its period of variation is 2 days 20 hours 48 minutes. This phenomenal character was first observed by Maraldi in 1694; but the duration of the change was determined by Goodricke in 1782. For two days and fourteen hours it continues at its brightest, and shines a glory in the heavens. Then its lustre suddenly begins to wane, and in three hours and a half is reduced to its minimum. Its weakest period, however, does not last more than about fifteen minutes. It then begins to increase in brightness, and in three hours and a half more it is restored to its full splendour; thus passing through its succession of changes in 2 days 20 hours 48 minutes.
This singular periodicity suggested to Goodricke the idea of some opaque body revolving around the star, and by interposing between it and the Earth cutting off a portion of its light. Algol is one of the most interesting of the welcome stars which kindle in the long Arctic darkness.