At 11.29 am AWST on Thursday 20 April 2023 the sun disappeared over Ningaloo. It reappeared a minute later.

The rest of Australia will experience a partial eclipse, and a chance to prepare for the big one, a total eclipse over Sydney in 2028.  

“Our last total solar eclipse was in November 2012, with Cairns right in the path of totality,” says amateur astronomer and eclipse chaser Terry Cuttle. “It’s been over a decade’s wait for another Aussie eclipse, so I’m on my way to Exmouth and Ningaloo – I wouldn’t miss it for the world!”

“Solar eclipses are spectacular,” says President of the Astronomical Society of Australia (ASA) Professor John Lattanzio. “Australia really is the lucky country with five total eclipses visible in various parts of the country over the next 15 years.”

Any single location on Earth is only likely to see a total eclipse once every few hundred years.

Dr Hessom Razavi of The Royal Australian and New Zealand College of Ophthalmologists (RANZCO), and the Lions Eye Institute, warns people to, “Never look directly at the Sun. It can cause serious and permanent eye damage, and that’s true even during a solar eclipse. Children’s eyes are especially vulnerable to damage”.

According to the ASA, the best ways to observe an eclipse are through:

• special-purpose ‘eclipse glasses’ or hand-held solar viewers with solar filters that meet the international standard
• using pinhole projection through a large card with a two-millimetre hole in the centre to project an image of the Sun onto another surface held about a metre away.

RANZCO advises that using solar eclipse glasses still carries some risks, so people must make sure their glasses meet the ISO 12312 2 standard and that they read and follow all safety advice and precautions, ensuring that there are no scratches or other damage. According to RANZCO, the only way to guarantee the prevention of solar retinopathy is to avoid all forms of direct sun viewing.

The ASA has created a comprehensive website at eclipse.asa.astronomy.org.au including sections on:

• safety: eclipse.asa.astronomy.org.au/how-to-view.
• the path of the eclipse: eclipse.asa.astronomy.org.au/eclipse-australia-2023/
• the next five eclipses: eclipse.asa.astronomy.org.au/future-eclipses/  

RANZCO has prepared advice for the public which can be found at bit.ly/41jMjPq.

Background

What is a solar eclipse?

A solar eclipse occurs when the moon passes between the Sun and Earth, casting a shadow on the Earth that either partially or fully blocks the face of the sun.

Solar eclipses are rare across the Solar System. Of the 200 confirmed moons orbiting six major planets, only the Earth’s moon is the right size and distance from its planet to neatly cover and obscure the solar disk and reveal the sun’s wispy corona.

A total solar eclipse occurs when the moon completely blocks the sun. Totality – the period of time the sun is totally obscured – only lasts up to seven minutes. It only occurs on the path of totality – the narrow path of the moon’s shadow moving across the Earth’s surface.

During an eclipse, two shadows are cast. The first is called the umbra. It is the dark centre of the eclipse shadow. The second shadow is called the penumbra and is a type of half-shadow.

Although a solar eclipse of some kind occurs somewhere on Earth at least twice each year, it is only in some of these events that the moon completely covers the sun. Sometimes the umbra misses Earth altogether, passing ‘above’ or ‘below’ our planet.

Australia’s Eclipse Quintet: 2023-2038

There will be five total solar eclipses visible in Australia over the next 15 years.

The 20 April 2023 eclipse’s path of totality passed over Australia in the Ningaloo region of WA, including the town of Exmouth. In Exmouth, totality began at 11:29:50 am (50 seconds past 11:29 am) AWST and lasted about one minute with the eclipsed sun 54 degrees above the horizon.

All of Australia will experience a partial eclipse, the closer an observer is to the path of totality the more the sun is obscured.

After the 2023 eclipse the next four will be:

• 22 July 2028 crossing the Kimberley in WA, NT, southwest Qld, NSW and passing through Sydney
• 25 November 2030 across SA, northwest NSW, southern Qld, ending at sunset in southeast Qld
• 13 July 2037 Through southern WA, southern NT, to Qld, passing over Brisbane and Gold Coast
• 26 December 2038 through central WA, SA, and along the NSW/Vic border.

For more information, visit: eclipse.asa.astronomy.org.au