It's been a long time since we've been able to see a total lunar eclipse from the West Coast of North America, but the wait is finally over. The total lunar eclipse that took place on April 15, 2014 was the first of two total lunar eclipses in 2014, and the first in a tetrad (four total lunar eclipses in series). The subsequent eclipses in the tetrad will occur on October 8, 2014, April 4, 2015 and September 28, 2015. This eclipse was especially well placed for observers in San Diego, California.
A lunar eclipse can only occur during a full moon when the orbital geometry of the Earth, the Moon and the Sun align for a short period of time. The Earth’s shadow has two parts: a darker inner section called the umbra and a lighter outer region called the penumbra. When the Moon only passes through the penumbra, we experience a Penumbral Eclipse. When the Moon passes through part of the umbra, we see a Partial Eclipse. When the Moon passes completely through the umbra, we experience a Total Eclipse.
