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- 1. Polaris Polaris (the North Star) lines-up almost perfectly with the Earth's axis over the north pole. For this reason, it does not appear to move in the night sky as the Earth rotates.
- 2. Polaris Polaris (the North Star) lines-up almost perfectly with the Earth's axis over the north pole. For this reason, it does not appear to move in the night sky as the Earth rotates.
- 3. Precession Over many years the Earth's axis slowly changes alignment as it rotates and revolves. This "wobble" is called Precession (much like a top or dreidel).
- 4. Star Luminosity and Temperature
- 5. Hertzsprung-Russel Diagrams Stars are classified using 2 properties: Luminosity – Magnitude of brightness from dim to very bright. Directly related to size. Temperature – How hot the star is. Directly related to colour (blue is hottest, red is coolest).