Celestial Cycles of Motion as Clocks (5305.0K)
Mars as it goes through retrograde motion (2537.0K)
The Stars (14954.0K)
Prominences (2361.0K)
HR Diagrams and Stellar Evolution (7025.0K)
The Universe (7140.0K)
Expansion and Red Shift (1417.0K)
Hubbles Law and the Age of the Universe (2444.0K)