Annular Solar Eclipse, Sunday, May 20, 2012

Contact: Rebecca Johnson
Editor, StarDate magazine
512-475-6763; [email protected]


This map shows the path of 'annularity,' with maximum eclipse (p.m., local time) for sites along the path. Areas outside the path of annularity will see a partial eclipse. (Inset: The bright Sun's outline around the dark Moon seen during an annular eclipse is called a 'Ring of fire.' Credit: sancho_panza/Wikipedia)

Eclipse Map (2187 × 1362 JPEG)2.71 MB

The Sun and Moon will team up to produce a brilliant ring of fire across the western United States on the afternoon of May 20, known as an annular solar eclipse, according to the editors of StarDate magazine. The eclipse occurs because the Moon will pass directly between Earth and Sun, covering the Sun's disk. The Moon will be near its farthest point from Earth, however, so it won't be quite big enough to cover the entire disk. Instead, a thin ring of sunlight will encircle the Moon.

For links to public viewing events a table of viewing times for different parts of the U.S., see StarDate's Ring of Fire page dedicated to this eclipse.

The annular eclipse will be visible across a narrow strip of Earth's surface that begins in China, wraps across the Pacific Ocean, and ends in the western United States. From the U.S., the path of the eclipse begins at the California-Oregon border around 6:24 p.m. PDT. It then sweeps to the east-southeast, ending over western Texas, as the Sun and Moon set, at 8:39 p.m. CDT. Along the centerline of the eclipse's path, "annularity" will last up to about five minutes.

Along this path, the sky will grow dusky, the air will cool noticeably, and leafy trees will cast odd ring-shaped shadows.

Most of the rest of the United States will see a partial eclipse, in which the Moon will cover a fraction of the Sun but will not be completely enfolded within the Sun's disk. Only the Eastern Seaboard will completely miss the shadow play.

Use caution to view the eclipse! While the Moon will hide most of the Sun's disk, the visible ring is still bright enough to cause eye damage. To view the eclipse, look through dark welder's glass, or build a "projector" by poking a pinhole in the side of a cardboard box and watching the sunlight projected inside the box.


Published bi-monthly by The University of Texas at Austin McDonald Observatory, StarDate magazine provides readers with skywatching tips, skymaps, beautiful astronomical photos, astronomy news and features, and a 32-page Sky Almanac each January.

Established in 1932, the McDonald Observatory near Fort Davis, Texas, hosts multiple telescopes undertaking a wide range of astronomical research under the darkest night skies of any professional observatory in the continental United States. McDonald is home to the consortium-run Hobby-Eberly Telescope, one of the world's largest, which will soon be upgraded to begin the HET Dark Energy Experiment. An internationally known leader in astronomy education and outreach, McDonald Observatory is also pioneering the next generation of astronomical research as a founding partner of the Giant Magellan Telescope.


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