Astronomy

Eras

Olympiads—rendered as I Olympiad, II Olympiad, &c.—are 4 year intervals, so that II is 4 years after I.

The year has three beginnings: Spring (March), the Consulship (January), and the Indiction (September).

Seasons

Spheres

The sphere of stars is called the firmament. That of the planets, the heavens. And of the elements, the earth. Each sphere of the heavens is itself called a heaven. The collection of all the spheres beyond that of water is sometimes also called the heavens, taken as a set of three: the spheres of air & fire, taken together as the 1st; all seven of the planets, the 2nd; and the firmament, the 3rd.

See the Physics page for more about æther.

Some conceive the world as semi-concentric spheres moved around each other, where east & west, and north & south, are intersecting circles. Some conceive the world as hemispheres instead, where east & west circle around north, and south, then, the extremity from the center. Christians say either view is acceptable, but Greeks only accept the spherical view. At any rate, each planet is moved in an additional sphere of its own within its respective sphere or hemisphere.

Planets

Crosses were added to the planetary symbols in the 16th century AD.

The symbols for each are from Roman astronomy. Saturn’s & Jupiter’s are stylized initials—κρ & ζε, respectively—Mars’ is a spear & shield, Venus’, a hand-mirror, Mercury’s, a caduceus, the Sun’s & the Moon’s, a solar beam & lunar crescent respectively.

Zodia

See Physics for more on stones.

Note: Each of the 12 zodia has 30 degrees, 10 for each decan, thus totalling 360. Man, correspondingly, has two sets of 12 ribs, & 360 joints.

Constellations

All the ancients were in harmony regarding the number of constellations—48, no more nor less. There was disagreement regarding what those were, but not how many.

The Ægyptians called the 36 non-zodiac constellations decans—meaning ten—because each marked the passage of 10 days. The Persians divided the constellations into 12 groups of 4—1 zodiac with 3 decans. An additional 5, now 5 1/4, days were added for a total of 365 days in the year. Thus, the decans told the days, & the zodia, the months.

The Persians distinguished a constellation called the bands from the fishes, and did not recognize the horse. Some Greeks did not distinguish the scales from the scorpion.

The first number is the count of stars in the constellation, the second, the count of unfigured stars, i.e., those not part of a constellation.

Northern Ecliptic

Northen Zodia

Southern Zodia

Southern Ecliptic

Many so-called constellations that are contemporaneously known are parts of these, e.g. the “southern cross” is the centaur’s right hindleg.

References

• John of Damascus, St. “An Exact Exposition of the Orthodox Faith” in: The Fount of Knowledge.
• Ptolemy. Almagest.