A rare solar eclipse will be visible Sunday in parts of the Western U.S. and Asia. CNN reported.

A Solar Eclipse occurs when the Sun, the Moon and the Earth are in a straight line with the Moon in between the Sun and the Earth.

During a solar eclipse if the Moon is close enough to the Earth it can block all the sunlight leaving the Sun look like a black disk. However, if the Moon is farther from the Earth it cannot fully block the disk, leaving a slim ring of sunlight. This makes the Sun appear as a thin ring behind the Moon – also called an Annular Solar Eclipse.

This weekend the eclipse will be visible late in the day on Sunday from northwestern Texas through New Mexico, northeastern Arizona, southern Utah, Nevada, northern California and southwestern Oregon late in the day on May 20. As the sun continues its path, the eclipse will then be visible over the North Pacific, in southern Japan and southern China on the morning of May 21.

The last annular eclipse appeared in the United States in 1994.

The  last annular eclipse appeared in India in 2010.