Total eclipse of the moon expected May 15-16, but will we see red?

A total lunar eclipse of the moon will be visible from across North America late Thursday, but whether the moon turns red depends on the presence of tiny particles in the Earth’s upper atmosphere, says Richard Heuermann, Outreach Program Coordinator in Washington University’s Department of Earth and Planetary Sciences in Arts & Sciences.

Visible from the United States for the first time in three years, the total eclipse of the moon will begin about 9:05 p.m. (CDT) as the umbra of the Earth’s shadow makes first contact with the moon.

As the moon passes almost directly through the center of the Earth’s shadow on May 15th, viewers will be treated to a lunar eclipse.

“Often the fully eclipsed moon turns a shade of red, as light from the sun skims the upper atmosphere of Earth and is deflected onto the moon,” Heuermann said. “Whether color appears, and what hue of red, is determined by particles in Earth’s upper atmosphere.”

Weather permitting, the eclipse should be visible from anywhere on the dark side of the Earth. The full moon will show a dark sliver on its east side that gets larger until the entire moon is covered. In St. Louis, totality begins at 10:14 p.m. and ends at 11:06 p.m. The umbra will leave the moon at 12:17 a.m.

Heuermann is available for media interviews on the science of lunar eclipses, including the often-asked question: Is it safe to stare at a lunar eclipse? Unlike eclipses of the sun — which can damage the eyes if viewed directly — lunar eclipses can be viewed safely with the naked eye, Heuermann said.

Heuermann is working with the Saint Louis Astronomical Society to promote two St. Louis-area public viewing locations: Parkway South High School and the Saint Louis Science Center. Participants are encouraged to bring binoculars, lawn chairs, still cameras with telephoto lens, tripods, video cameras and telescopes. For more information, contact Jim Small, Saint Louis Astronomical Society at (314) 909-7211 or e-mail at