A celestial phenomenon is underway, with observers in the UK able to see a crescent sun while viewers in the Arctic enjoy an annular solar eclipse.
An annular eclipse occurs when the sun and moon are exactly in line with the Earth, but the apparent size of the moon appears slightly smaller than the sun. This causes the sun to appear as a very bright ring, or annulus, in a phenomenon known as the “ring of fire”. The full phenomenon will be visible on Thursday to those watching in locations such as Canada, Greenland, and northern Russia.
In the unlikely event anyone is watching from the Nares Strait, which lies between Ellesmere Island and Greenland, they will experience an eclipse lasting almost four minutes – a duration greater than anywhere else.
Weather permitting, observers in the UK and Ireland, as well as locations ranging from the Caribbean to northern Africa, will see a crescent sun instead of a ring – a partial eclipse – as in these locations the sun, moon, and Earth do not perfectly line up. The Met Office has said parts of the UK will be cloudy although most regions are expected to remain dry.
In places such as Stornoway on the Isle of Lewis it is expected that skygazers will see about 40% of the sun eclipsed at the height of the event, with the best views having been expected there shortly before 11.20am. However, those further south will also be able to witness a partial eclipse.
People in central and south-east England will have clear spells to witness the spectacle, according to the Met Office, andThursday morning, observers in these areas will be able to see nearly a third of the sun being blocked out by the moon.
The Met Office spokesperson Stephen Dixon said: “Thursday morning will see more cloud than recent days over east, south-east and much of southern England though some good breaks are likely with sunny spells. Similar conditions are likely over east and north-east Scotland with all these areas having the best visibility of the solar eclipse.
“There will be clear spells over much of central and south-east England. Much of the far south-west of England, Wales, Northern Ireland, western and central Scotland will have more in the way of cloud cover, and whilst this may thin by day, the likelihood is that visibility of the eclipse will be somewhat fleeting.
“It will be dry for many, particularly eastern areas, whilst western areas and high ground here are more likely to see some light rain and drizzle.”
Dr Emily Drabek-Maunder, an astronomer at the Royal Observatory Greenwich, said the “ring of fire” would be seen from Russia, Greenland and northern Canada.
She said: “From the UK, the annular solar eclipse will be a partial eclipse, meaning that we’ll only see the moon pass in front of a small part of the sun.”
Drabek-Maunder said the phenomenon would begin at 10.08am on Thursday in the UK, with the maximum eclipse occurring at 11.13am, when the moon would cover close to one-third of the sun. The partial eclipse will end at 12.22pm.
The last annular eclipse took place in June 2020 and was visible to observers in a narrow band from west Africa to the Arabian peninsula, India and southern China.
A total solar eclipse is also expected in 2021 – a phenomenon whereby the moon completely obscures the surface of the Sun. The event, which is due to occur on 4 December, will be visible in Antarctica and is expected to last just under two minutes.
Even though a large part of the solar disc will be covered, looking at the partially eclipsed sun without appropriate protection can cause serious and permanent damage to the eyes.
Drabek-Maunder said: “The eclipse from the UK will only be visible with certain techniques and optical aids. Never look at the sun directly or use standard sunglasses – it can cause serious harm to your eyes.”
It is also not wise to look at the sun through binoculars, telescopes or a telephoto lens on an SLR camera.
She suggested using a simple pinhole projector, solar eclipse viewing glasses – which can be purchased online – or special solar filters that can fit on telescopes, to observe the eclipse.
“You can make a projector by poking a small hole into a piece of card. Hold the card up to the sun so that light shines through the hole and on to a piece of paper behind the card. You will be able to see the shape of the sun projected on to the piece of paper and watch its shape change as the moon passes in front of the sun.”