The United States will be the center of the astronomical universe May 20. On that Sunday afternoon, the Moon will pass directly in front of the Sun for those located within a narrow path that runs from the Pacific coast near the California-Oregon border to West Texas. Observers along this track will see the Moon cover approximately 94 percent of the Sun, reducing our star to a ring of sunlight. Viewers in parts of China and Japan (where it will be the morning of May 21) will also witness this annular solar eclipse. And people with clear skies anywhere within a couple of thousand miles of this path will see a partial solar eclipse.