Draft: this lesson was written with AI help and has not yet been read by a human editor.
1 What your class asks
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
Curriculum expectations, with their official codes
- E2.4 identify the types of bodies in space that emit light and those that reflect light
2 Before you start
A thought to carry into the lesson.
3 The lesson
How do you tell a source from a lit body?
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.
Go deeper
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.
Why they did it
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.
Think about it
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?
Into the museum
- 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.
Try this
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.
4 Carry it further
Where this lesson leads in the museum.
5 Check yourself
Nothing here is marked or sent anywhere. It is for you.
In your own words: what does Solar and lunar eclipses have to do with this lesson?
Compare with the card
Where the Moon's light comes from. Al-Farghani shows that the moon is lit by the sun's light, so the half of its disc facing the sun is bright. At opposition the moon enters the earth's shadow, which is a cone narrowing as it extends. Of the two bodies, which gives light, and which is only lit?
In your own words: what does Hilal (the crescent and the lunar month for the law) have to do with this lesson?
Compare with the card
The lit part of the Moon, first sighted. The Kuwaiti Encyclopaedia of Fiqh gives hilal, technically, as the first sighting of the lit part of the moon on the first night. It adds that the size of the crescent is no guide to the start of the month; what counts is the night of sighting. Which body lights the part of the Moon that is sighted?
I can now
Notes
- 1. Ontario Ministry of Education, The Ontario Curriculum: Science and Technology, Grades 1–8 (2022)
- 2. al-Farghani, Elementa astronomica (Golius, Amsterdam 1669), p. 294
- 3. al-Farghani, Elementa astronomica (Golius, Amsterdam 1669), p. 234
- 4. al-Farghani, Elementa astronomica (Golius, Amsterdam 1669), p. 235
- 5. al-Farghani, Elementa astronomica (Golius, Amsterdam 1669), p. 246
- 6. Muruj al-Dhahab — al-Masʼudi, p.519