Celestial spheres

“ As in the schemes of several of his predecessors, the fixed stars lie on a sphere which revolves daily about an axis through the earth; the motion of each of the other bodies is produced by a combination of other spheres, the centre of each sphere lying on the surface of the preceding one. For the sun and moon three spheres were in each case necessary: one to produce the daily motion, shared by all the celestial bodies; one to produce the annual or monthly motion in the opposite direction along the ecliptic ”

“ The observer in this sphere is located on the surface of the earth at north latitude 41° 50'. Celestial spheres constructed for localities having other latitudes north or south would be placed at other angles and certain other constellations would be shown. The stars are represented by tiny perforations in the sphere, different sizes being used for stars of different magnitudes. The size
North-south Cross Section of Sphere. ”

“ The Horizon, the Zenith, and the Meridian. First, let us consider what is the ordinary appearance of the sky. When we go out of doors on a clear night we see the heavens in the shape of a great dome arched above us and filled with stars. What we thus see is one half of the spherical shell of the heavens which surrounds us on all sides, the earth being apparently placed at its centre. The other half is concealed from our sight behind, or below, the earth. This spherical shell, of which only one half is visible to us at a time, is called the celestial sphere. ”

“ Most of us at the present day have been taught in childhood that the stars are at different distances, and that this sphere has in consequence no real existence. The early peoples had no knowledge of this, and for them the celestial sphere really existed, and was often thought to be a solid sphere of crystal. ”

“ It was believed that the planets and stars were set in a series of concentric orbs or spheres, each so perfectly transparent that bodies in the outer ones were visible through all the intervening ones. The drawing shows the order of the spheres and the system of the universe according to Ptolemy. The earth is in the center enclosed by the sphere of the moon, beyond are the concentric spheres of Mercury, Venus, the sun, Mars, Jupiter and Saturn. Outside of all are the crystalline heavens and the abode of the blessed. ”

“ With the pole (north for us in the northern hemisphere) as the center of the dial face the stars appear to move in a direction the reverse of that in which the hands of a clock are made to move. The astronomer, that is, the celestial globe maker, thinks of himself as placed beyond the vaulted heavens in which the stars appear to be located, and as looking down upon this vaulted dome as on the surface of his celestial globe. ”

“ They are in a fair state of preservation, the celestial, however, being somewhat damaged through attempts to turn the sphere, which does not move freely on its axis within the meridian and the horizon circle. ”

“ The solar system, amidst a countless number of other systems as large as itself, rolls ever silently through space in the direction of the constellation of Hercules. The great spheres of which it is composed spin and spin through the eternal void ceaselessly and noiselessly. ”

“ This motion of the heavenly bodies is known to be an apparent one merely, and caused by the turning of our own earth upon its axis. A man standing upon the earth's surface can look up and see above him one-half the great celestial vault, gemmed with twinkling stars, and bearing, perhaps, within its ample curve one or two serenely shining planets and the lustrous moon. But at any given moment the observer can see nothing of the other half of the heavenly sphere. ”

“ The celestial globe revolves on the axis of the equator, the gores being made to terminate at the poles of the ecliptic. Constellations are represented so far as they have been named by astronomers to date, the several figures being artistically drawn, on which color has been somewhat sparingly employed. ”

“ Upon the sphere, besides the principal circles of the celestial globe, the Zodiac is placed, of a breadth sufficient to contain the apparent path of the moon, with all the stars over which the moon can pass, also the ecliptic, and the heliocentric orbits of all the planets. The Earth in the planetarium has a moveable horizon, to which a large moveable brass circle within the sphere may be set coincident, representing the plane of the horizon continued to the starry heavens. ”

“ There can be no doubt that the celestial spaces — at least within the region that the earth traverses — are crowded with angular bits of stony matter, ranging in weight from thousands of pounds down to particles as light as the finest dust. Every night millions of the smaller bits fall swiftly upon our earth’s atmosphere, sparkle for a moment as shooting stars, and are burnt into vapor by the heat engendered from their friction in the atmosphere. ”

“ If, now, we wish to ascertain the exact location of a star on the celestial sphere, as we would that of New York, London, or Paris, on the earth, we measure along the hour circle running through it, its declination, or distance from the celestial equator, and then, along its parallel of declination, we measure its right ascension, or distance from the vernal equinox. ”

“ When less than one tenth the size of your sun, these fiery spheres rapidly contract, condense, and cool. When upwards of thirty times its size—rather thirty times the gross content of actual material—suns readily split into two separate bodies, either becoming the centers of new systems or else remaining in each other's gravity grasp and revolving about a common center as one type of double star. ”

“ Since the Fixed Stars are prodigious spheres of fire, like our Sun, and at inconceivable distances from one another, as well as from us, it is reasonable to conclude they are made for the same purposes that the Sun is; each to bestow light, heat, and vegetation on a certain number of inhabited Planets, kept by gravitation within the sphere of it’s activity. ”

“ As the Earth turns round the line NCS, the whole Heavens MOLl seem to turn round the same line, but the contrary way. It is plain that this observer has the Poles constantly in his Horizon, and that his Horizon cuts the Diurnal paths of all the Celestial bodies perpendicularly and in halves. ”

“ The celestial sphere, therefore, as we now possess it, is not simply a collection of unmeaning names, associated with a group of stars in no way connected with them, which have been imposed at various epochs by capricious imagination, but in most instances, if not in all, they embody a history, which, if we could trace it, would probably lead us to astronomical facts, indicating the where and the when of their first introduction ”

“ At the center of the sphere, the inner surface of which, as stated above, represented the starry heavens, was placed a small ball, about 15 cm. in diameter, representing the earth. The great globe, driven by water power, was therefore made to appear to revolve around this central terrestrial globe. A representation of the sun, made of glass, had its own proper motion along the circle of the ecliptic, and a representation of the moon likewise was made to move in its own proper course. ”

“ If we consider with attention the periodical variations of the spots we shall not be long in coming to the conclusion that it is impossible to connect them directly with any one astronomical function in particular, for the spots appear in a sudden and irregular manner which contrasts in a striking degree with the continuous and progressive action of the ordinary perturbations which we meet with in the study of Celestial Mechanics. ”

“ Celestial globe in which are to be seen more clearly and more distinctly set forth the stars according to their places and positions, that is, their degrees of longitude and latitude where they have been placed in the firmament by the Creator of the Universe. ”

“ Rotation of the Celestial Sphere.—It is well known that the sun and the majority of the stars rise in the east, and set in the west. In our latitude there are certain stars in the north which never disappear below the horizon. ”

“ The constellations in all their splendor would circle before their eyes with the revolution of their planet about the sun, and with the exception of the sun itself—which they could see by making a journey to the opposite hemisphere—all the members of the solar system would pass in succession through their mid-heaven, and two of them would present themselves with a magnificence of planetary display unknown on the earth. ”

“ Our little Earth revolves round the mighty Sun; the Sun itself and the whole solar system are moving with inconceivable velocity towards a point in the constellation of Hercules; together with all the nearer stars it forms a cluster in the heavens, which appears to our eyes as the Milky Way; while outside our star cluster again are innumerable others, which far transcend, alike in magnitude, in grandeur, and in distance, the feeble powers of our finite imagination. ”

“ Heaven is fashioned on a transcendently large scale. It is not a single sphere, but a universal chain of vast and luminous star-groups, scattered harmoniously throughout the infinite regions of space, so that a part of it lies suspended preciously near to our own Solar System. ”