D. Circles of the celestial sphere (Lines 462–558)

These orbits lie like rings, four in number, chief in interest and in profit, if thou wouldst mark the measures of the waning and the waxing of the Seasons. On all are set beacon lights, many in number, all every way closely penned together. The circles are immovable, and fitted each to other, but in size two are matched with two.

If ever on a clear night, when Night in the heavens shows to men all her stars in their brightness and no star is borne faintly gleaming at the mid-month moon, but they all sharply pierce the darkness – if in such an hour wonder rises in thy heart to mark on every side the heaven cleft by a broad belt, or if someone at they side point out that circle set with brilliants – that is what men call the Milky Way. A match for it in colour thou wilt find no circle wheel, but in size two of the four belts as large, but the other two are far inferior.

Of the lesser circles one [Tropic of Cancer] is night to Boreas at his coming, and on it are borne both the heads of the Twins and the knees of the stedfast Charioteer, and above him are the left shoulder and shin of Perseus. It crosses Andromeda’s right arm above the elbow. Above it is set her palm, nearer the north, and southward leans her elbow. The hoofs of the Horse, the head and neck of the Bird and Ophiuchus’ bright shoulders wheel along this circle in their course. The Maiden is borne a little to the South and does not touch the Belt, but on it are the Lion and the Crab, Thereon are they both established side by side, but the circle cuts the Lion beneath the breast and belly lengthwise to the loins, and the Crab it cuts clean through by the shell where thou canst see him most clearly cut, as he stands upright with his eyes on either side of the Belt. The circle is divided, as well as may be, into eight parts, whereof five in the daytime wheel on high above the earth and three beneath the horizon. In it is the Turning-point of the Sun in summer [solstice]. This circle is set round the Crab in the North.

But there is another circle [Tropic of Capricorn] to match in the South. It cuts through the middle of Aegoceros, the feet of Hydrochoüs, and the tail of the sea-monster, Cetus, and on it is the Hare. It claims no great share of the Dog, but only the space that he occupies with his feet. In it is Argo and the mighty back of the Centaur, the sting of Scorpio, and the Bow of the bright Archer. This circle the sun passes last as he is southward borne from the bright north, and here is the Turning-point of the sun in winter. Three parts of eight of his course are above and five below the horizon.

Between the Tropics a Belt [the Equater], peer of the grey Milky Way, undergirds the earth with imaginary line bisects the sphere. In it the days are equal to the nights both at the waning of the summer and the waxing of the spring [the Equinoxes]. The sign appointed for it is the Ram and the knees of the Bull – the Ram being borne lengthwise through it, but of the Bull just the visible bend of the knees. In it are the Belt of the well-starred Orion and the coil of the gleaming Hydra: in it, too, the dim-lit Crater and the Crow and the scanty-starred Claws and the knees of Ophiuchus are borne. But it has no share in the Eagle, but near it flies the mighty messenger of Zeus. Facing the Eagle wheel the head and neck of the Horse.

These three Belts [Tropics of Cancer, Tropic of Capricorn, and the Equater] are parallel, and at right angles to the Axis which they surround and which is the centre of them all, but the fourth [the Ecliptic] aslant is fixed athwart the Tropics: they on opposite sides of the Equator support it at either limit, but the Equator bisects it. Not otherwise would a man skilled in the handicraft of Athena join the whirling Belts, wheeling them all around, so many and so great like rings, just as the Belts in the heavens, clasped by the transverse circle, hasten from dawn to night throughout all time. The three Belts rise and set all parallel but ever single and the same is the pint where in due order each rises or sets at East or West. But the fourth circle passes over as much water of ocean as rolls between the rising Aegoceros, and the rising of the Crab: as much as it occupies in rising, so much it occupies in setting. As long as is the ray cast to heaven from the glance of the eye, six times as long a line would subtend this Belt. Each ray, measured of equal length, intercepts the two constellations. This circle is called the Belt of the Zodiac.

In it is the Crag; after the Crab the Lion and beneath him the Maiden; after the Maiden the Claws and the Scorpion himself and the Archer and Aegoceros, and after Aegoceros Hydrochoüs. Beneath him are enstarred the Two Fishes and after them the Ram and next the Bull and the Twins. In them, twelve in all, has the sun his course as he leads on the whole year, and as he fares around this belt, all the fruitful seasons have their growth.

Half this Belt is set below the hollow of the horizon, and half is above the earth. Every night six constellations of this circle’s twelve set and as many rise; as long is each night ever stretched as half the belt rises above the earth from the fall of night.