Solar eclipse plunges South America into darkness as 300,000 skygazers watch on in wonder

Here's what you need to know...

• A solar eclipse is a rare natural phenomenon that darkens the sky
• It happens when you’re in the shadow cast by the Moon, which is fully blocking the Sun
• This only happens when the Sun, Moon and Earth are aligned on a straight line
• A total eclipse is when the disk of the Sun is fully obscured by the Moon
• Total solar eclipses will occur somewhere on Earth approximately every 18 months
• Eclipses were considered ominous by ancient cultures, because the Sun disappears during the day in minutes
• However, solar eclipses are now a very popular spectacle that can attract tourists
• It’s important to not look directly at the Sun during a solar eclipse, as it can lead to permanent eye damage, and even blindness
• It’s recommended that people use special eye protection, or watch the event on screens instead

Here's the official advice from the American Astronomical Society...

Looking directly at the Sun is unsafe except during the brief total phase of a solar eclipse (“totality”), when the Moon entirely blocks the Sun’s bright face, which will happen only within the narrow path of totality.

The only safe way to look directly at the uneclipsed or partially eclipsed Sun is through special-purpose solar filters, such as “eclipse glasses” or handheld solar viewers.

Homemade filters or ordinary sunglasses, even very dark ones, are not safe for looking at the Sun; they transmit thousands of times too much sunlight.

Always inspect your solar filter before use; if scratched, punctured, torn, or otherwise damaged, discard it. Read and follow any instructions printed on or packaged with the filter.

Always supervise children using solar filters.

If you normally wear eyeglasses, keep them on. Put your eclipse glasses on over them, or hold your handheld viewer in front of them.

Stand still and cover your eyes with your eclipse glasses or solar viewer before looking up at the bright Sun. After looking at the Sun, turn away and remove your filter — do not remove it while looking at the Sun.

Do not look at the uneclipsed or partially eclipsed Sun through an unfiltered camera, telescope, binoculars, or other optical device.

Similarly, do not look at the Sun through a camera, telescope, binoculars, or any other optical device while using your eclipse glasses or handheld solar viewer — the concentrated solar rays could damage the filter and enter your eye(s), causing serious injury.