Western Slope Skies - 9/26/14

Sep 26, 2014

Pre-Dawn Lunar Eclipse

The second total lunar eclipse of 2014 will occur in the pre-dawn hours of Wednesday, October 8th. Nearly the entire eclipse will be visible from Western Colorado.

A lunar eclipse occurs when the Earth passes directly between the Sun and the Moon. As a result, the Earth prevents sunlight from reaching the Moon, casting a shadow on the lunar surface. If you were standing on the Moon during one of these eclipses, you would see a solar eclipse as the Earth blocked the view of the Sun!

During a total lunar eclipse, the Moon often takes on a dark red or orange color.    Because a lunar eclipse happens when the Moon enters Earth’s shadow, you might think that no sunlight should reach the Moon, and it would be invisible to us. However, the Earth has an atmosphere that refracts, or “bends,” sunlight passing through it towards the Moon’s surface. Red light is bent more and scattered less than blue light so most of the sunlight that makes it to the Moon during a lunar eclipse is red in color. This is the same effect that causes sunsets to appear red and orange. The amount of light bent towards the Moon depends on how much dust is in the Earth’s atmosphere. This means that no two lunar eclipses look exactly the same! Lunar eclipses following large volcanic eruptions tend to be darker red, because volcanic ash and aerosols scatter more of the non-red light.  

While lunar eclipses happen at least twice per year, oftentimes the Moon will only skirt Earth’s shadow, resulting in a less impressive event. Total lunar eclipses, where the entire Moon is in shadow, are less common. Two more total lunar eclipses will be visible from Colorado in 2015 but then we will have to wait until 2018 to see another!  

The October 8th eclipse technically begins at 2:15 AM local time, but it will be at least an hour later before the Moon appears noticeably darker to the naked eye. The time of greatest eclipse will be at 4:54 AM, so set your alarm and cross your fingers for clear skies!

Western Slope Skies is produced by members of the Black Canyon Astronomical Society.  This episode was written & voiced by Zach Schierl.