On the Revolutions of the Heavenly Spheres

11. On three other acronychal An "acronychal" observation is made when a planet is directly opposite the Sun, appearing at its brightest and visible all night. sightings of Jupiter recently observed.
12. Confirmation of the uniform motion of Jupiter.
13. Assigning the positions of Jupiter's motion.
14. On perceiving the commutations The "commutation" or "parallax" refers to the apparent change in a planet's position caused by the Earth's own movement around the Sun. of Jupiter, and its altitude in proportion to the Earth’s annual revolution.
15. On the star of Mars.
16. On three other midnight sightings original: "fulsionibus," referring to the planet's brilliance at opposition. of the star Mars, recently observed.
17. Confirmation of the motion of Mars.
18. Fixing the positions of Mars.
19. The size of Mars's orbit in parts, relative to the Earth's annual orbit being counted as one.
20. On the star of Venus.
21. The ratio between the diameters of the orbits of Earth and Venus.
22. On the twin motion of Venus.
23. On examining the motion of Venus.
24. On the positions of Venus's anomaly The "anomaly" is the angle used to track a planet's position relative to its furthest point from the center of its orbit..
25. On Mercury.
26. On the position of the highest and lowest apsides The "apsides" are the points in an orbit closest to and farthest from the center of motion. of Mercury.
27. The extent of Mercury's eccentricity "Eccentricity" describes how much an orbit deviates from a perfect circle. and the symmetry of its orbits.
28. Why Mercury's elongations original: "digressiones" appear larger near the side of a hexagon Referring to a point 60 degrees away from the planet's furthest orbital point. than those occurring at its perigee The "perigee" is the point in an orbit closest to the Earth..
29. Examination of Mercury's mean motion.
30. On more recent observations of Mercury's motions.
31. On fixing the positions of Mercury.
32. On another reason for approach and recession The "accessus ac recessus" refers to the theory of the planet moving closer to and further from the center of its path..
33. On the tables of prosthaphaereses A "prosthaphaeresis" is a mathematical correction added or subtracted to the average motion to find a planet's true, observed position. for the five wandering stars In the 16th century, "wandering stars" was the standard term for planets (Saturn, Jupiter, Mars, Venus, and Mercury)..
34. How the positions of these five stars are calculated in longitude.
35. On the stations and retrogradations original: "repedationibus" of the five wandering stars.
36. How the times, places, and arcs of regressions are determined.

1. General exposition on the latitudinal digression In astronomy, "latitude" measures how far north or south a planet moves from the ecliptic—the Sun's apparent path. of the five wandering stars.
2. Hypotheses of the circles by which these stars are carried in latitude.
3. The extent of the inclination of the orbits of Saturn, Jupiter, and Mars.
4. On explaining the latitudes of these three stars in general, and any others.
5. On the latitudes of Venus and Mercury.
6. Mercury. On the second latitudinal transit of Venus and Mercury according to the tilt of their orbits at apogee and perigee.
7. The angles of the tilting for both stars, Venus and Mer-
8. cury The name "Mercury" is split between Chapter 7 and 8 in the original layout.. On the third type of latitude for Venus and Mercury, which they call Deviation.
9. On the calculation of the latitudes of the five wandering stars.