- Why is the vernal equinox both a time and a place?
- How many different definitions can you give of equinox and solstices?
- What is the “Age of Aquarius”?
- Why is the Tropic of Cancer called the Tropic of Cancer even though the Sun is not in Cancer in late June?
- What do you need to know to know the maximal altitude of the Sun on a given day? Give a formula that determines the maximal altitude of the Sun on a given day.
- How long does the Sun lag behind the stars every day?
- How long does the Moon lag behind the Sun every day?

Helmer Aslaksen

Department of Mathematics

National University of Singapore

helmer.aslaksen@gmail.com