How Common Are Eclipses?
Approximately every six months, the Moon is near the ecliptic plane for about 34.5 days. During this period—called an eclipse season—the Moon, the Sun, and Earth can align to produce eclipses. There is at least one solar eclipse and one lunar eclipse each eclipse season; however, not every eclipse is easily viewable.
Because the Moon’s shadow is relatively small, people can only see each solar eclipse along a part of Earth’s surface. It is rare to see a total solar eclipse because the path of the umbra is less than 100 miles wide and totality only lasts a few minutes at any location.
In contrast, the shadow of Earth is relatively large, so all lunar eclipses are visible from anywhere on the night side of Earth. The light from the Moon decreases just a small amount during a penumbral lunar eclipse, so it is very hard to observe. However, partial and total lunar eclipses, when the Moon is in Earth’s umbra, can last for hours and are easily observable.
This map shows the paths of totality for all total solar eclipses from 2001 to 2025. Click to see larger version.
Take Notes
Why is it more common to see a lunar eclipse than a solar eclipse? Refer to the map on this page and/or the model of the Earth–Moon system on page 6.
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