By Geoff Gaherty, Starry Night Education — for Space.com
Just two weeks after the huge ‘super Moon’ wowed skywatchers around the world, the heavens will offer up another observing treat — a solar eclipse on May 20 that should be visible from much of western North America.
The May 20 event is what’s known as an annular solar eclipse, in which the Moon blocks out most of the sun but leaves a ring of light visible around its circumference.
It should be quite a spectacular sight for favorably placed — and appropriately careful — skywatchers throughout Asia, the Pacific region and parts of North America.
Annular solar eclipses: The basics
As the Moon revolves around Earth, it passes between our planet and the sun once every 29.5 days. Most of the time,the Moon zips either above or below the Sun, and no eclipse occurs. [Video: How to View the May 20 Solar Eclipse]
But if the Moon is close to one of its orbital nodes — the points where the orbits of Earth and the Moon cross — the Moon will pass directly in front of the Sun and block its light. If the Moon is also close to apogee,the point that marks its farthest distance from the Earth, it will not completely cover the Sun, and we get an annular eclipse.
‘Annular’ comes from the Latin word annulus (ring) and refers to the fact that a ring of Sun shines all around the Moon.