The Sun, the planets, the Moon and comets

This lesson asks you to identify components of the solar system, including the Sun, Earth and other planets, natural satellites, comets, asteroids and meteoroids, and to describe their main physical characteristics. The museum offers two records: al-Farghani's account of the Sun, Moon and planets moving along the zodiac, and a report of a tailed star in 905 AH; the class brings the other bodies and their physical characteristics, which the museum does not hold. ¹

For each body you read about, write its name, what the record says about its place or movement, and what you would still have to find out from another source.

In the record on the second motion, al-Farghani says the moon has its own sphere in the second motion; its movement along the zodiac from west to east, contrary to the first motion, is accomplished together with the motion of the epicycle ^{2 3}. The five planets' motion in the second motion is detailed in chapter fourteen ⁴.

No sentence of the record on al-Farghani says why he wrote. It shows that the index of the Latin edition lists thirty chapters ⁵, and that the chapters show him estimating the earth's circumference from a degree measured by the cubit in al-Ma'mun's days ⁶.

The report of 905 AH tells where a tailed star rose, where its tail lay and where it moved, while al-Farghani's second motion tells how the Sun and the planets move along the zodiac. Which of the two gives you more to compare from one night to the next, and why?

• The second motion: the proper motion of the sun and planets along the zodiac.
• A comet appears, 905: the report in Shadharat al-Dhahab.
• Al-Farghani: the author of the Thirty Chapters and what the sources say of his time.

Make a table of the bodies named in the second motion and in the report of 905 AH: the name, what the record says about it, and what you would need to find out elsewhere.