How to safely look at Venus passing across the face of the Sun

People could permanently damage their eyesight and even risk blindness if they look directly at Venus passing across the face of the Sun on June 8th warned the Government's Chief Medical Officer today as he offered eye-safe alternatives.

On 8th June between approximately 6.00am and midday BST the planet Venus will cross the face of the Sun as seen from Earth for the first time since 1882.

Chief Medical Officer Professor Sir Liam Donaldson said: "We want viewers of the first transit of Venus since 1882 to enjoy it safely. Children are particularly vulnerable as they will be tempted to take a peek - we must do all we can to protect their eyesight.

"Under no circumstances should viewers look at this event directly. The risks to sight from looking at the Sun are very real and could lead to irreversible damage to eyesight and even blindness.

"The safest way to view the event is on the television or live webcasts on the internet. Using a small telescope to project the event onto a screen is safe but I must stress that observation directly through a telescope, binoculars or camera is not safe, even just to line up the projection. In addition sunglasses, and photographic film are totally inadequate and should not be used to view the transit under any circumstances."

Anita Lightstone from the Royal National Institute of the Blind, said: "It is vital that people take the issue of eye safety and the transit seriously, if they do not, what should be a great event could end in tragedy. People who look directly at the sun during the transit, even for as little as 5 seconds, risk permanent eye damage, even blindness".

Andrew Elliott from the The Royal College of Ophthalmologists, said: "People may be tempted to take 'just one quick glimpse' through binoculars or a telescope so putting their sight at risk. But damage to the back of the eye can happen in an instant and once it has happened, there is no treatment."

This advice has the support of the Royal College of Ophthalmologists, College of Optometrists, Royal National Institute of the Blind and incorporates advice from the Royal Astronomical Society.

1. Further information on the safe viewing of the transit is available from: www.transitofvenus.org/safety.htm
2. For those wishing to make their own projector the Orpington Astronomical Society provide the following instructions with pictures on their webiste (www.chocky.demon.co.uk/oas/venus.html)

To observe the transit you will need a small telescope, two pieces of white card and some kind of tripod (a chair will do).

If you have a telescope cut one hole in the centre of one of the pieces of card. Push the card onto the telescope and fix with masking tape.

Mount the small telescope onto the tripod and fix it in such a way that it can be pointed into the sky towards the Sun.

Get someone to hold the other piece of white card a short distance away from the eye piece. Slacken the mounting so that you can move the telescope with ease.

DO NOT UNDER ANY CIRCUMSTANCES TRY TO ALIGN THE TELESCOPE WITH THE SUN, BY LOOKING THROUGH IT.

Move the telescope around until the 'smallest shadow' has been achieved onto the white card, you will quickly notice that every time you get the 'smallest shadow' the image of the Sun jumps across the card. once the image of the Sun can be seen on the white card fix the mounting in place.

The telescope should never be left unattended and under no circumstances should anyone look through the eyepiece. Care should also be taken to ensure that no part of the telescope becomes overheated.

During the six hour transit you will have to move the set up in order to follow the Sun. However, because you are using a small telescope you will find several minutes of comfortable viewing before the apparatus has to be reset.

For those who do not own a tripod, a high backed wooden chair is also ideal, but following the Sun may prove a little tricky.

College of Optometrists, RNIB, Royal Astronomical Society, Royal College of Ophthalmologists