Bodies that give light and bodies that reflect it

This lesson asks you to identify which types of bodies in space give off light and which reflect it. The museum offers one record on how al-Farghani explains the Moon's light and one on the first sighting of the Moon's lit part; the class brings the stars, the planets and the other bodies, which the museum does not hold for this lesson. ¹

For each body you read about, write what the record says lights it, and whether the record says it shines by itself or is lit by another body.

In his notes on al-Farghani, Golius gives an example: a lunar eclipse Ibn Yunus observed on the night of Thursday in the year 368 of the Hijra, with the Persian, Alexandrian and Diocletian dates given; the eclipse's diameter was more than eight fingers and less than nine ². In the same section of the record on eclipses, al-Farghani shows that the moon takes its light from the sun, its bright half facing it, and that a lunar eclipse occurs when the moon enters the earth's shadow at or near a node ^{3 4}.

No sentence of the record on al-Farghani says why he wrote his book. It shows only that Golius places his time in al-Ma'mun's era, counting him among the astronomers of that age, and notes that the author mentions al-Ma'mun's observatories in chapters five and eight ⁵, and that al-Mas'udi counts him among those who engaged in the sciences of the heavens ⁶.

Al-Farghani says the half of the Moon facing the Sun is bright, and the encyclopaedia says that what counts for the start of a month is the night on which the lit part is first sighted. Why might it matter, for seeing a thin lit part on a given night, where the Sun and the Moon stand?

• Eclipses: how al-Farghani explains the moon's light from the sun.
• The hilal: what the Kuwaiti Encyclopaedia of Fiqh says about the lit part of the moon and the crescents as times.
• Al-Farghani: the author of the Thirty Chapters and what the sources say of his time.

Read what al-Farghani says about the lit half of the Moon. Draw the Sun and the Moon, shade the half you think is lit, and write under your drawing which body gives light and which is only lit.