Eclipse Series, Four Blood Moons

April 15, 2014

Skywatchers Catch a 'Blood Moon' Eclipse and Mars - View Gallery   NBC - April 15, 2014

The first total lunar eclipse in more than two years turned the moon into a cosmic red ball early Tuesday and there's still more to come. Total lunar eclipses occur when Earth is positioned precisely between the sun and the full moon. Because of the tilt of the moon's orbit, total eclipses don't happen all that often - about twice in the course of three years, on average. When they do, it can be a spectacular sight: The darkened moon takes on a reddish glow because of the sunlight refracted by Earth's atmosphere.

Red Moon, Green Beam   NASA - April 18, 2014

This is not a scene from a sci-fi special effects movie. The green beam of light and red lunar disk are real enough, captured in the early morning hours of April 15. Of course, the reddened lunar disk is easy to explain as the image was taken during this week's total lunar eclipse. Immersed in shadow, the eclipsed Moon reflects the dimmed reddened light of all the sunsets and sunrises filtering around the edges of planet Earth, seen in silhouette from a lunar perspective. But the green beam of light really is a laser. Shot from the 3.5-meter telescope at Apache Point Observatory in southern New Mexico, the beam's path is revealed as Earth's atmosphere scatters some of the intense laser light. The laser's target is the Apollo 15 retroreflector, left on the Moon by the astronauts in 1971. By determining the light travel time delay of the returning laser pulse, the experimental team from UC San Diego is able to measure the Earth-Moon distance to millimeter precision and provide a test of General Relativity, Einstein's theory of gravity. Conducting the lunar laser ranging experiment during a total eclipse uses the Earth like a cosmic light switch. With direct sunlight blocked, the reflector's performance is improved over performance when illuminated by sunlight during a normal Full Moon, an effect fondly known as The Full Moon Curse.

Waterton Lake Eclispe   NASA - April 17, 2014

Recorded on April 15th, this total lunar eclipse sequence looks south down icy Waterton Lake from the Waterton Lakes National Park in Alberta, Canada, planet Earth. The most distant horizon includes peaks in Glacier National Park, USA. An exposure every 10 minutes captured the Moon's position and eclipse phase, as it arced, left to right, above the rugged skyline and Waterton town lights. In fact, the sequence effectively measures the roughly 80 minute duration of the total phase of the eclipse. Around 270 BC, the Greek astronomer Aristarchus also measured the duration of lunar eclipses - though probably without the benefit of digital clocks and cameras. Still, using geometry, he devised a simple and impressively accurate way to calculate the Moon's distance, in terms of the radius of planet Earth, from the eclipse duration. This modern eclipse sequence also tracks the successive positions of Mars, above and right of the Moon, bright star Spica next to the reddened lunar disk, and Saturn to the left and below.

The Turquoise Fringe - April 17, 2014

Lunar eclipses are supposed to be red, yet when the Moon passed through Earth's amber shadow on April 15th, many observers witnessed a softly-glowing band of turquoise blue. The source of the turquoise is ozone. During a lunar eclipse, most of the light illuminating the Moon passes through the stratosphere, and is reddened by scattering. However, light passing through the upper stratosphere penetrates the ozone layer, which absorbs red light and actually makes the passing light ray bluer. This can be seen, he says, as a turquoise fringe around the red.

Under a Blood Moon: 1st Total Lunar Eclipse of 2014 Wows Stargazers (Photos) - April 15, 2014

The moon took on an eerie blood-red hue early Tuesday during the first total lunar eclipse of 2014, a celestial sight that wowed potentially millions of stargazers across North and South America. The total lunar eclipse of April 15 lasted about 3.5 hours between late Monday and early Tuesday, with the Earth's shadow slowing darkening the face of the so-called "Blood Moon" in a jaw-dropping sight for stargazers willing to stay up extra late or rise super-early for the event.

  'Blood moon' eclipse seen over Americas   BBC - April 15, 2014

Skywatchers in the Americas have caught a rare celestial show caused by the Earth's shadow falling across the Moon. The Moon changed color from orange to blood red or brown in a total lunar eclipse. The total lunar eclipse unfolded over three hours as the Moon moved into the Earth's shadow.

Science, Bailey's Beads, History, Mythology, Astrology, Pseudoscience