Caption: A very simplified diagram of the Aristotelian cosmos as understood in Renaissance Europe. To be precise, calendar year 1524.

1. The diagram is exactly geocentric as Aristotelian cosmos demands.

2. However, all the compounded celestial spheres of the astronomical objects with their offset rotational axes are NOT explicitly shown.

   Showing them was too tricky and much more than most people wanted to see.

   Yours truly gets the feeling that only mathematical astronomers and natural philosophers cared about the compounded celestial spheres much anyway.

3. You see the main celestial spheres of the planets, Sun, and Moon in a cross section through the ecliptic.

   However, they are offset from the astronomical objects as in the Ptolemaic physical model of the Solar System (see Wikipedia: Ptolemy: Astronomy; ptolemaic_physical_model.html), and NOT as in pure Aristotelian cosmos.

4. The celestial spheres carry, relatively slowly, the astronomical objects eastward or (counterclockwise in the diagram) relative to the celestial sphere of the stars and the zodiac which rotate westward once per day.

5. Both the zodiac constellations (duplicated with slight offsets for reasons beyond yours truly's understanding in the 2nd and 3rd outermost circular panels) and the zodiac signs (in the outermost circular panels) are illustated.

6. The zodiac signs are 30° segments of the ecliptic starting at the vernal equinox which is also called is the First Point Aries (which is the start of the sign Aries represented by the astronomical symbol ♈ in the diagram).

7. Circa year 500 BCE, the zodiac signs approximately enclosed the zodiac constellations for which zodiac signs are named. The axial precession has shifted the zodiac signs by ∼ 30° westward from zodiac constellation since then.

8. The Coelum empireum habitaculum dei et omnium electorum (the Empyrean of God and the Elect) either is or is beyond the celestial sphere of the stars: it's unclear to yours truly---and maybe everyone else---which it is.

9. Shown are the astronomical symbols for the Solar-System astronomical objects known then:

   Sun ☉, Moon ☽, Mercury ☿, Venus ♀, Earth ⊕ (NOT shown), Mars ♂, Jupiter ♃, Saturn ♄.

   and for the zodiac (zodiac constellation linked by name; zodiac sign by linked by astronomical symbol):

   Aries ♈, Taurus ♉, Gemini ♊, Cancer ♋, Leo ♌, Virgo ♍, Libra ♎, Scorpius ♏, Sagittarius ♐, Capricornus ♑, Aquarius ♒, Pisces ♓.

10. The ordering of the planets (which include Sun and Moon) and the celestial sphere of the stars going outward from the Earth is the usual one for ancient Greek astronomers including Aristotle (384--322 BCE)???: Earth: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, celestial sphere of the stars.

    The ordering of the planets is by decreasing angular velocity around the Earth NOT counting the daily rotation of the whole sky:

    1. The argument for the ordering of the planets etc. was that if the spatial speed of the planets etc. was the roughly the same for all the planets etc. (NOT counting the daily rotation of the whole sky), then the angular velocity should decrease with increasing circumference and radius of the orbit.

    2. This argument is a half truth. For, superior planets the angular velocity should decrease with increasing distance from the Earth which relative to the superior planets is close to the approximate center of their orbits the Sun. The argument is sort of right for the and the Moon which does actually physically orbit the Earth.

    3. For the inferior planets and the Sun the argument is NOT true in any straightforward way since the mean distance to Mercury and Venus is the Earth-Sun distance and it's unclear how to apply the argument since the angular velocities of Mercury and Venus have large variations. In fact, the ordering of Mercury, Venus, and Sun was disputed by the ancient Greek astronomers and sometimes different orderings of Mercury, Venus, and Sun were suggested I think????.

    4. The outermost of the celestial spheres of Aristotelian cosmology was the celestial sphere of the stars. The celestial sphere of the stars evolved into the modern celestial sphere which is NOT a physical thing, but a sky mapping tool.

    5. There is no conclusive argument for the location of the celestial sphere of the stars known ancient Greek astronomers. But since the motions of the planets are measured relative to the fixed stars, it is natural to think of the fixed stars as forming a background. The ancient Greek astronomers just followed this natural path without dissent as far as yours truly knows.

11. The ancient Greek astronomers could NOT find the real ordering or structure of the Solar System because they could NOT measure Solar System distances, except that they did eventually determine that the Moon was ∼ 60 Earth radii away from the Earth. Ptolemy (c.100--c.170 CE) found an apogee value of 64 and 1/6 Earth radii of some kind (see Wikipedia: Lunar distance: Lunar eclipse). The modern perigee distance = 55.89 mean orbital radius = 60.2687 and apogee distance = 63.76 all in Earth equatorial radii (R_eq_⊕ = 6378.1370 km) Earth equatorial radii (see Wikipedia: Lunar distance: Value but yours truly's values are more accurate/precise).