Students, this evening we'll have a chance to observe a phenomenon that we've discussed several times in class. Tonight there will be a lunar eclipse. As we've said, when an eclipse of the Moon occurs, the Earth passes between the sun and the Moon. Therefore, the shadow of the Earth moves across the surface of the Moon and obscures it. Because you won't be looking at the Sun, it is not necessary to use the special lenses and filters that you need when observing a solar eclipse. You can observe lunar eclipse with your unaided eye or with a telescope and phonograph it with an ordinary camera. So if the weather is not cloudy tonight, go out and take a look at this eclipse of the Moon. I'm sure you'll find it interesting