Venus as morning and evening star (905.0K)
Retrograde Motion and the Ptolmaic System (1553.0K)
Retrograde Motion and the Copernican System a (840.0K)
Retrograde Motion and the Copernican System b (825.0K)
Keplers First Law (1297.0K)
Keplers Second Law (1265.0K)
Keplers Third Law a (5303.0K)
Keplers Third Law b (6485.0K)
Jupiters Atmosphere (1654.0K)
Comet Tails (3338.0K)
Meteors (2242.0K)