When the partial solar eclipse occurs tomorrow morning, Tuesday 4 January, do not look directly at the sun or you risk permanently damaging your eyesight and even blindness, warns the UK government’s Interim Chief Medical Officer Dame Sally Davies.

Anita Lightstone, Programme Director UK Vision Strategy, from the Royal National Institute of Blind People, said it was “vital” that people take this advice seriously:

“People who look directly at the sun, even for as little as five seconds, risk permanent eye damage, even blindness.”

The safest way to watch the partial solar eclipse, when the moon passess between the earth and the sun, is on the television, or on the internet where it will be shown on live webcasts, said a statement that Dame Sally Davies released last week, where she warned that:

“Under no circumstances should people look directly at the sun during a partial eclipse.”

The risks of doing so are very real and could lead to irreversible damage to eyesight and even blindness,” she added.

Children are particularly vulnerable and may be tempted to have a look and Dame Sally urged parents to explain the danger to them.

“We would not wish to see another case like the young boy who lost his central vision back in October 2005 through looking directly at a partial eclipse in his school playground,” she said.

It is not safe to look at the eclipse with the naked eye, or even observe it through a telescope, binoculars or camera. Sunglasses and photographic film are also “wholly inadequate” said the statement, which appears on the Department of Health website.

Only specially designed filters that bear the appropriate CE mark should be used to view the eclipse directly. The CE mark means the product has met EU consumer safety, health or environmental requirements.

The warning has the backing of the Royal College of Ophthalmologists, the College of Optometrists, the Royal National Institute of Blind People and incorporates advice from the Royal Astronomical Society.

The partial solar eclipse, the first solar eclipse of 2011, will be visible over most of Europe, North Africa and northeastern Asia.

In the UK it will already have started when the sun rises in London at 8.06 am on Tuesday 4 January, and slightly later in the North (eg Manchester 8.24 am, Glasgow 8.46 am). For the UK, it ends shortly after 9.30 am.

How much of the sun the moon will obscure will vary considerably across the UK. For example, in the middle of the eclipse, when viewed from the South East of England, two thirds of the sun will be obscured, while from the Western Isles of Scotland, just a quarter is covered.

At maximum eclipse, London will see nearly three quarters of the sun covered by the moon, Liverpool and Plymouth will see nearly 70% obscured and Glasgow barely 40%.

The eclipse occurs at the Moon’s ascending node in eastern Saggittarius. The shadow will first touch Earth’s surface in northern Algeria, and as it travels east, Western Europe will see it as a partial eclipse at sunrise.

The greatest eclipse will be at 08.50 in Sweden, according to the US Government’s National Aeronautics and Space Administration (NASA), when the “axis of the Moon’s shadow will pass a mere 510 km above Earth’s surface”.

People in Cairo, Jerusalem, Istanbul and Tehran will see a “large magnitude partial eclipse”, and people in central Russia, Kazakhstan, Mongolia and northwest China, will see the eclipse at sunset.

The eclipse tomorrow is the first of six due to happen in 2011. NASA says the others will be on:

  • 01 June: Partial Solar Eclipse,
  • 15 June: Total Lunar Eclipse,
  • 25 November: Partial Solar Eclipse, and
  • 10 December: Total Lunar Eclipse.

For centuries, humans have tried to explain the Sun in terms of their own beliefs and culture.

Whether cast as a god, a demon, a mischievous spirit, an omnipotent creator or a ruthless taker of life, most cultures have portrayed the Sun as the main controller of life on Earth.

For example, in Greek mythology, Helios is the young god of the sun, born of Hyperion and Theia. At dawn each morning he rises from the ocean and rides across the sky in his chariot pulled by four horses Pyrois, Eos, Aethon and Phlegon.

Helios once allowed his son Phaeton to drive the chariot but the inexperienced youth could not control the four horses and fell towards his death.

In early Christian art, Christ is sometimes represented as Helios. There is a mosaic showing him thus in the necropolis beneath the St. Peter in Rome.

The longest solar eclipse to have occurred in recent times was the solar eclipse on July 22nd, 2009 from India, Southeast Asia, and China.

This lasted an incredibly long 6 minutes and 39 seconds; the longest solar eclipse until 2132, says the Stanford Solar Center, whose website has a gallery of photos sent in by enthusiasts.

Sources: Department of Health (30 Dec 2010, press release), NASA Eclipse website, Stanford Solar Center, Encyclopedia Mythica.

Written by: Catharine Paddock, PhD