Frequency of eclipses
Typically 2 solar and 2 lunar eclipses per year
Why is it so much easier to see a lunar eclipse?
- lunar -- half the world can see
- solar -- only seen on narrow eclipse path f. 3-15
- spot ~ 200 km wide sweeps across earth
- travels 1000 mph
- have to wait ~ 400 y to see solar eclipse at one location
Why are the Sun and Moon the same apparent angular diameter (0.5o)?
- Sun much bigger than the Moon, but
- Moon much closer than the Sun
- The two factors exactly compensate
- accident of nature
- in 400 million years, no more solar eclipses!