How to spot October’s ‘ring of fire’ solar eclipse across the Americas

An annular solar eclipse is passing through North and South America on 14 October. In the United States, the full eclipse will be visible in parts of Oregon, Nevada, Utah, Arizona, New Mexico and Texas, which are on the path of annularity. However, most of North America will be able to see a partial eclipse as part of the moon passes in front of the sun.

What is an annular eclipse? 

Annular eclipses, also known as “ring of fire” eclipses, occur when the moon doesn’t appear quite big enough in the sky to cover the entire sun in a total solar eclipse, instead leaving a bright ring visible around the edges.

Solar eclipses happen when the moon passes between the sun and Earth, casting a shadow over an area of the planet as it moves. The moon’s orbit isn’t perfectly circular, so its size in the sky changes slightly over the course of each month. Total solar eclipses occur when the moon is close enough to Earth that it appears just as large as the sun in the sky. Annular eclipses occur when the sun, moon and Earth line up perfectly, but the moon is just a bit too far away to appear big enough to block the sun entirely.

Where will the eclipse be visible?

At the height of the eclipse on 14 October, the moon will cover 91 per cent of the disc of the sun. This will be visible across the western US, and the best places to view the spectacle there will be along a path running through Oregon, Nevada, Arizona, New Mexico and Texas. The eclipse will also pass through Mexico, Belize, Honduras, Nicaragua, Costa Rica, Panama and Colombia, before sweeping across Brazil.

The annular eclipse will be visible along a strip of Earth just about 200 kilometres wide, and the best viewing locations will see the eclipse for up to 5 minutes and 17 seconds. Areas outside that narrow path will see a partial solar eclipse, in which the moon doesn’t line up just right to produce a ring of fire. The partial eclipse will be visible across most of the US, Canada, South America, and even the western edge of Africa.

When will the eclipse be visible in the US?

According to NASA, most cities along the path of annularity will see a partial solar eclipse begin over an hour before the peak, while the annularity – when the moon passes right in front of the sun – will be visible for five minutes or less. The chart below shows when these major US cities will see the annularity.

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How rare is an annular eclipse?

Annular solar eclipses occur somewhere in the world every year or two, similar to the frequency of total solar eclipses. The next total eclipse will be on 8 April, 2024, and it will follow a similar path to the upcoming ring of fire eclipse, passing through a swathe of the Americas.

However, the next time an annular eclipse will pass through the contiguous United States will be in 2044, and it will only be partially visible in three states – Montana, North Dakota and South Dakota.

How to watch the solar eclipse

During partial and annular eclipses, there is no point when the moon completely covers the sun, so it is never safe to look directly at the eclipse without eye protection. You should only use eclipse glasses – which are thousands of times darker than sunglasses – and handheld solar viewers that comply with the ISO-12312-2 international standard.

Never look at the eclipse through binoculars, telescopes or camera lenses, even when wearing eclipse glasses, as the sun’s powerful rays can cause severe and permanent eye injuries.

You can also view the eclipse using an indirect viewing method, such as a pinhole projector.