A "Prime-Time" Lunar Eclipse

By: J. Kelly Beatty February 15, 2008 0

Contacts:
J. Kelly Beatty, Executive Editor
855-638-5388 x2148, [email protected]

Alan MacRobert, Senior Editor
855-638-5388 x2151, [email protected]

Note to Editors/Producers: This release is accompanied by high-quality graphics and an animation; see end of release.

For more information, including tips on how to photograph the eclipse, please direct your readers/viewers to our online general-interest story.

Wherever clear skies prevail, skywatchers all across the Americas will have front-row seats when the full Moon dives through Earth's shadow on Wednesday evening, February 20th. In Europe and West Africa, the eclipse occurs during the early-morning hours of Thursday, the 21st.

Unlike a solar eclipse, each stage of a lunar eclipse is visible to everyone on the Moon-facing side of Earth at once; we’re all looking together.

So Earth’s shadow will totally engulf the Moon from 10:00 to 10:52 p.m. Eastern Standard Time for those on the East Coast, where the Moon will be high in a completely darkened sky.

Meanwhile, in the Far West, totality occurs from 7:00 to 7:52 p.m. Pacific Standard Time, with the Moon closer to the eastern horizon. In fact, anyone along the Pacific Coast will see moonrise just as the partial eclipse is getting under way.

Here are the key event times for the eclipse, given for four North American time zones:

Total Eclipse of the Moon, February 20, 2008
Eclipse stage	PST	MST	CST	EST
Partial eclipse begins	5:43 p.m.	6:43 p.m.	7:43 p.m.	8:43 p.m.
Total eclipse begins	7:00 p.m.	8:00 p.m.	9:00 p.m.	10:00 p.m.
Total eclipse ends	7:52 p.m.	8:52 p.m.	9:52 p.m.	10:52 p.m.
Partial eclipse ends	9:09 p.m.	10:09 p.m.	11:09 p.m.	12:09 a.m.

This is the third of three total lunar eclipses within a year's time. The previous total lunar eclipse, last August 28th, favored the Far West. The one before that, on March 3, 2007, favored eastern North America and Europe.

After this one, however, comes a prolonged dry spell. The next total lunar eclipse visible anywhere won't occur until December 20-21, 2010 — nearly three years from now.

During the eclipse, the Moon makes a broad triangle with the bright planet Saturn and the somewhat fainter star Regulus, marking the heart of Leo, the Lion.

How and Why

A total lunar eclipse occurs when the Sun, Earth, and Moon form a nearly straight line in space, so that the full Moon passes through Earth's shadow. Unlike a solar eclipse, which requires special equipment to observe safely, you can watch a lunar eclipse with your unaided eyes. Binoculars or a telescope will enhance the view dramatically.

The outer part of Earth's shadow, called the penumbra, creates only a slight dusky shading on the lunar disk. But as the Moon begins to move into the central and darkest part of Earth's shadow, the umbra, there's an obvious and ever-larger "bite" in the full Moon. The partial eclipse is then under way.

The total eclipse begins when the Moon is fully within the umbra. On February 20th, totality lasts 52 minutes. But the Moon likely won't disappear completely. It usually glows as an eerie, coppery red disk in the sky, as sunlight scattered around the edge of our atmosphere paints the lunar surface with a warm glow. This is light from all the sunrises and sunsets that are in progress around Earth at the time.

Sky & Telescope is making the following illustrations, photographs, and animation available to editors and producers. Permission is granted for one-time, nonexclusive use in print and broadcast media, as long as appropriate credits (as noted in each caption) are included. Web publication must include a link to SkyandTelescope.com.

On Wednesday evening, February 20th, North Americans with clear skies can see the last total lunar eclipse until late 2010. On that night the Moon spends 52 minutes passing through the umbra, or darkest part, of Earth's shadow. High-resolution versions of this illustration are available without time labels and labeled for the Eastern, Central, Mountain, and Pacific time zones.

S&T: Gregg Dinderman

A lunar eclipse occurs when the Moon passes through the shadow cast by the sunlit Earth. When the Moon enters the outer penumbra, where just part of the Sun's light is blocked, it becomes only slightly dimmer. Only when it passes into the shadow’s core, the umbra, does it look markedly darker. This illustration is available as a publication-quality JPEG (399 kilobytes); it is also available without labels (344 kilobytes).

Sky & Telescope illustration by Gregg Dinderman.

Taking a break from Game 4 of the World Series on October 27, 2004, Sky & Telescope editor in chief Rick Fienberg snapped this view of that evening's total eclipse of the Moon. Click on the image for a larger version.

Sky & Telescope photograph by Richard Tresch Fienberg.

Aligning his camera on the same star for nine successive exposures, Sky & Telescope contributing photographer Akira Fujii captured this record of the Moon’s progress dead center through the Earth’s shadow in July 2000. This image is available as a publication-quality JPEG (1.5 megabytes).

Courtesy Akira Fujii and Sky & Telescope.

In this sequence of 291 images taken during a total lunar eclipse on September 27, 1996, 1 second represents 30 minutes of elapsed time. Coloring has been added to simulate the Moon's appearance when it was completely within Earth's shadow; the totally eclipsed Moon has been brightened for clarity. During totality, dark, murky blobs are seen crossing the lunar disk — an effect caused by variations in the tiny amount of sunlight that leaks onto the Moon after being refracted (bent) through Earth's atmosphere. This animation can be viewed or downloaded as a broadcast-quality (3.7-megabyte) QuickTime animation.

Sky & Telescope animation by Craig M. Utter and Gregg Dinderman; images courtesy António Cidadão.

Sky Publishing (a New Track Media company) was founded in 1941 by Charles A. Federer Jr. and Helen Spence Federer, the original editors of Sky & Telescope magazine. In addition to Sky & Telescope and SkyandTelescope.com, the company publishes two annuals (Beautiful Universe and SkyWatch), as well as books, star atlases, posters, prints, globes, and other fine astronomy products.