Total lunar eclipse delivers promised "Blood Moon"

CBS NEWS

A total lunar eclipse turned the moon a reddish hue early Tuesday morning, drawing crowds into the night air across the country.

The "Blood Moon" effect peaked between the hours of 3 a.m. and 4:30 a.m. Eastern, and the cosmic color change was perfectly placed for most viewers in North and South America -- at least those fortunate enough to have dodged cloud cover.


Photo show a time lapse of the moon during a total lunar eclipse
Photo show a time lapse of the moon during a total lunar eclipse, as seen from Mexico City, April 15, 2014. REUTERS
If the atmosphere conspired against your neighborhood and blocked the view, fear not, this eclipse marked the beginning of a tetrad, a series of four total lunar eclipses in a row. The next three total eclipses will occur on Oct. 8, 2014, April 4, 2015, and the final one on Sept. 28, 2015.
The start of Tuesday's lunar eclipse marked the second of nine tetrads this century, according to astronomer Fred Espenak. The last tetrad occurred in 2003 and the next is set to take place in 2032. There were five tetrads in the 20th century.

"Italian astronomer Giovanni Schiaparelli first... noticed that tetrads were relatively plentiful during one 300-year interval, while none occurred during the next 300 years," Espenak explained to CBS News. "For example, there are no tetrads from 1582 to 1908, but 17 tetrads occur during the following 2 and 1/2 centuries from 1909 to 2156. The [approximate] 565-year period of the tetrad 'seasons' is tied to the slowly decreasing eccentricity of Earth's orbit."
As the Earth positions itself between the sun and the moon, a reddish hue surrounds the moon due to the indirect sunlight that manages to reach and illuminate it. Sunlight first passes through the Earth's atmosphere, filtering out most of the blue colored light, resulting in the reddish color. Earth's atmosphere can also refract some of the light, causing a small fraction to reach and illuminate the moon, Espenak explains on his website.