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1	Astr 1050 Fri. Sep. 9, 2005 Extra Credit Articles, HW Due/Solutions Finish Ch. 2, The Sky Start Ch. 3: Cycles in the Sky Seasons Angular Size formula Eclipses Phases of the moon Milankovitch Hypothesis deferred to end of semester, if time (w/ global warming topic)
2	Start Chapter 3: Cycles in the Sky Motion of the Sun through the year Plot position of Sun relative to stars, over one full year. Complicated by fact you can’t see Sun and stars at same time. Once you have full map of sky, you can work this out by seeing what stars are opposite sun 12 hours later.
3	Plotting the Ecliptic on the Celestial Sphere
4	Consider the Sun’s daily motion thru the year
5	How the Sun’s location affects the seasons:
6	Special Locations on the Earth
7	Effect of Elliptical Orbit on Climate Seasons almost entirely due to TILT of Earth Seasons opposite (not the same) in N & S Hemispheres Earth’s orbit slightly elliptical Slightly closer to the sun in N. Hemisphere Winter But this changes as tilt precesses in 26,000 yr cycle Expect N. Hemisphere winter to be slightly milder Positions of continents and oceans actually more important Effect is important for Mars -- more elliptical orbit Cyclic variations in climate as tilt precesses (and tilt and ellipticity also gets slightly larger and smaller VERY IMPORTANT TOPIC (Re: Global Warming)
8	Why are the planets found near the ecliptic?
9	Superior vs. Inferior Planets
10	Inferior Planets
11	Lunar/Solar Tides (exaggerated!)
12	More on tides
13	Angular sizes
14	The Angular Size of the Moon How big is the moon? Have you ever seen the moon near the horizon? Has it looked huge, much larger than when it is high in the sky? Next full moon is Saturday, Sep. 17. Have a look! After we do phases you will know where and when to look!
15	Shadows and Eclipses
16	Types of eclipses
17	Solar eclipses
18	Eclipse Facts Longest possible total eclipse is only 7.5 minutes. Average is only 2-3 minutes. Shadow sweeps across Earth @ 1000 mph! (Compare with scene in The Mummy Returns!) Birds will go to roost in a total eclipse. The temperature noticeably drops. Totally predictable (even in ancient times, e.g., the Saros Cycle, eclipse pattern repeats every 6585.3 days or 18 years, 11 1/3 days).
19	Eclipses and Nodes
20	Variations in Solar Eclipses
21	Phases of the Moon and its orbit around the Earth (1).
22	Phases of the Moon and its orbit around the Earth (2).