GEK1506 Heavenly Mathematics & Cultural Astronomy, Tutorial 6, Solutions to Selected Questions

  1. 2 a.m.
  2. Mercury, Venus.
  3. Mars, Jupiter and Saturn are visible to the naked eye. Then there is Uranus, Neptune and Pluto (if the latter is considered a planet).
  4. Venus can only be seen in the morning or the evening, while Mars can be seen any time of the night.
  5. The inferior planets oscillate back and forth. The superior planets usually move eastward with respect to the stars (same way as the yearly motion of the Sun), but when we overtake them, they retrograde, i.e., move westward.

Helmer Aslaksen
Department of Mathematics
National University of Singapore