Astronomy for Amateurs - Camille Flammarion (ebook reader with android os TXT) 📗
- Author: Camille Flammarion
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If you will now follow me into the Houses of the Sun you will readily recognize them again, provided you have a clear picture of the principal stars of the Northern Heavens. First, you see the Ram, the initial sign of the Zodiac; because at the epoch at which the actual Zodiac was fixed, the Sun entered this sign at the vernal equinox, and the equator crossed the ecliptic at this point. This constellation, in which the horns of the Ram (third magnitude) are the brightest, is situated between Andromeda and the Pleiades. Two thousand years ago, the Ram was regarded as the symbol of spring; but owing to the secular movement of the precession of the equinoxes, the Sun is no longer there on March 21: he is in the Fishes.
To the left, or east of the Ram, we find the Bull, the head of which forms a triangle in which burns Aldebaran, of first magnitude, a magnificent red star that marks the right eye; and the Hyades, scintillating pale and trembling, on its forehead. The timid Pleiades, as we have seen, veil themselves on the shoulder of the Bull—a captivating cluster, of which six stars can be counted with the unaided eye, while several hundred are discovered with the telescope.
Next the Twins. They are easily recognized by the two fine stars, α and β, of first magnitude, which mark their heads, and immortalize Castor and Pollux, the sons of Jupiter, celebrated for their indissoluble friendship.
Cancer, the Crab, is the least important sign of the Zodiac. It is distinguished only by five stars of fourth and fifth magnitudes, situated below the line of Castor and Pollux, and by a pale cluster called Præsepe, the Beehive.
The Lion next approaches, superb in his majesty. At his heart is a gorgeous star of first magnitude, α or Regulus. This figure forms a grand trapezium of four stars on the celestial sphere.
The Virgin exhibits a splendid star of first magnitude; this is Spica, which with Regulus and Arcturus, form a triangle by which this constellation can be recognized.
The Balance follows the Virgin. Its scales, marked by two stars of second magnitude, are situated a little to the East of Spica.
We next come to the eighth constellation of the Zodiac, which is one of the most beautiful of this belt of stars. Antares, a red star of first magnitude, occupies the heart of the venomous and accursed Scorpion. It is situated on the prolongation of a line joining Regulus to Spica, and forms with Vega of the Lyre, and Arcturus of the Herdsman, a great isosceles triangle, of which this latter star is the apex.
The Scorpion, held to be a sign of ill luck, has been prejudicial to the Archer, which follows it, and traces an oblique trapezium in the sky, a little to the east of Antares. These two southernmost constellations never rise much above the horizon for France and England. In fable, the Archer is Chiron, the preceptor of Jason, Achilles and Æsculapius.
Capricorn lies to the south of Altaïr, on the prolongation of a line from the Lyre to the Eagle. It is hardly noticeable save for the stars α and β of third magnitude, which scintillate on its forehead.
The Water-Carrier pours his streams toward the horizon. He is not rich in stars, exhibiting only three of third magnitude that form a very flattened triangle.
Lastly the Fishes, concluding sign of the Zodiac, are found to the south of Andromeda and Pegasus. Save for α, of third magnitude, this constellation consists of small stars that are hardly visible.
These twelve zodiacal constellations will be recognized on examining the chart (Figs. 10–11).
We must now visit the stars of the Southern Heavens, some of which are equally deserving of admiration.
Capricorn, Archer, Scorpion, Balance, Virgin, Lion.
It should in the first place be noted that the signs of the Zodiac and the Southern Constellations are not, like those which are circumpolar, perpetually visible at all periods of the year. Their visibility depends on the time of year and the hour of the night.[4]
In order to admire the fine constellations of the North, as described above, we have only to open our windows on a clear summer's evening, or walk round the garden in the mysterious light of these inaccessible suns, while we look up at the immense fields in which each star is like the head of a celestial spear.
But the summer is over, autumn is upon us, and then, too soon, comes winter clothed in hoar-frost. The days are short and cold, dark and dreary; but as a compensation the night is much longer, and adorns herself with her most beautiful jewels, offering us the contemplation of her inexhaustible treasures.
First, let us do homage to the magnificent Orion, most splendid of all the constellations: he advances like a colossal giant, and confronts the Bull.
This constellation appears about midnight in November, in the south-eastern Heavens; toward eleven o'clock in December and January, due south; about ten in February, in the south-east; about nine in March, and about eight in April, in the west; and then sets below our horizon.
It is indisputably the most striking figure in the sky, and with the Great Bear, the most ancient in history, the first that was noticed: both are referred to in the ancient texts of China, Chaldea, and Egypt.
Eight principal stars delineate its outline; two are of the first magnitude, five of the second, and one of the third (Fig. 12). The most brilliant are Betelgeuse (α) and Rigel (β): the former marking the right shoulder of the Colossus as it faces us; the second the left foot. The star on the left shoulder is γ or Bellatrix, of second magnitude; that of the right foot, χ, is almost of the third. Three stars of second magnitude placed obliquely at equal distances from each other, the first or highest of which marks the position of the equatorial line, indicate the Belt or Girdle. These stars, known as the Three Kings, and by country people as the Rake, assist greatly in the recognition of this fine constellation.
A little below the second star of the Belt, a large white patch, like a band of fog, the apparent dimensions of which are equal to that of the lunar disk, is visible to the unaided eye: this is the Nebula of Orion, one of the most magnificent in the entire Heavens. It was discovered in 1656 by Huyghens, who counted twelve stars in the pale cloud. Since that date it has been constantly studied and photographed by its many admirers, while the giant eye of the telescope discovers in it to-day an innumerable multitude of little stars which reveal the existence of an entire universe in this region.
Orion is not merely the most imposing of the celestial figures; it is also the richest in sidereal wonders. Among these, it exhibits the most complex of all the multiple systems known to us: that of the star θ situated in the celebrated nebula just mentioned. This marvelous star, viewed through a powerful telescope, breaks up into six suns, forming a most remarkable stellar group.
This region is altogether one of the most brilliant in the entire firmament. We must no longer postpone our homage to the brightest star in the sky, the magnificent Sirius, which shines on the left below Orion: it returns every year toward the end of November. This marvelous star, of dazzling brilliancy, is the first, α, in the constellation of the Great Dog, which forms a quadrilateral, the base of which is adjacent to a triangle erected from the horizon.
When astronomers first endeavored to determine the distance of the stars, Sirius, which attracted all eyes to its burning fires, was the particular object of attention. After long observation, they succeeded in determining its distance as 92 trillion kilometers (57 trillion miles). Light, that radiates through space at a velocity of 300,000 kilometers (186,000 miles) per second, takes no less than ten years to reach us from this sun, which, nevertheless, is one of our neighbors.
The Little Dog, in which Procyon (α, of first magnitude) shines out, is above its big brother. With the exception of α, it has no bright stars.
Lastly, toward the southern horizon, we must notice the Hydra, Eridanus, the Whale, the Southern Fish, the Ship, and the Centaur. This last constellation, while invisible to our latitudes, contains the star that is nearest to the Earth, α, of first magnitude, the distance of which is 40 trillion kilometers (25 trillion miles).
The feet of the Centaur touch the Southern Cross, which is always invisible to us, and a little farther down the Southern Pole reigns over the icy desert of the antarctic regions.
In order to complete the preceding descriptions, we subjoin four charts representing the aspect of the starry heavens during the evenings of winter, spring, summer, and autumn. To make use of these, we must suppose them to be placed above our heads, the center marking the zenith, and the sky descending all round to the horizon. The horizon, therefore, bounds these panoramas. Turning the chart in any direction, and looking at it from north, south, east, or west, we find all the principal stars. The first map (Fig. 13) represents the sky in winter (January) at 8 P.M.; the second, in spring (April) at 9 P.M.; the third, in summer (July) at the same hour; the fourth, the sky in autumn (October) at the same time.
And so, at little cost, we have made one of the grandest and most beautiful journeys conceivable. We now have a new country, or, better, have learned to see and know our own country, for since the Earth is a planet we must all be citizens of the Heavens before we can belong to such or such a nation of our lilliputian world.
We must now study this sublime spectacle of the Heavens in detail.
CHAPTER III THE STARS, SUNS OF THE INFINITEA Journey through Space
We have seen from the foregoing summary of the principal Constellations that there is great diversity in the brightness of the stars, and that while our eyes are dazzled with the brilliancy of certain orbs, others, on the contrary, sparkle modestly in the azure depths of the night, and are hardly perceptible to the eye that seeks to plumb the abysses of Immensity.
We have appended the word "magnitude" to the names of certain stars, and the reader
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