On April 4th, the full Moon passed through the shadow of the Earth, producing a brief but beautiful lunar eclipse. For nearly 5 minutes, the normally-gray face of the Moon turned red. Jack Jewell photographed the transformation above Boulder, Colorado.
"Perfectly clear skies greeted us for the brief total lunar eclipse in twilight," says Jewell. "The Photographer's Ephemeris helped me chose the perfect location to catch the eclipse above the Flatirons of Boulder with the National Center for Atmospheric Research (NCAR) in the foreground."
While most people saw red, observers using telescopes noticed a second hue. Astronomy professor Jimmy Westlake of Stagecoach, Colorado, photographed a blue band as the Moon was emerging from totality.
"This gives new meaning to the phrase 'blue moon,'" says Westlake. "The photo is a 4-second exposure at the prime focus of a Celestron Nexstar 8-inch telescope."
The blue band is caused by ozone. Atmospheric scientist Richard Keen of the University of Colorado explains: "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 using binoculars or a small telescope as a turquoise-blue border around the red.