Viewing the solar eclipse
The Department of Health has issued the following eye safety advice for viewing the partial eclipse on Tuesday 4 January.
"Between 8am and 9.30am, the moon will pass across the face of the sun, creating a partial eclipse of the sun. If you're planning to view this amazing spectacle, make sure you know the risks and how to protect your eyes.
Looking directly at the sun can result in serious eye damage or even blindness. The absence of pain or discomfort while looking at an eclipse does not mean damage to the eyes will not occur. Permanent damage to the retina can be caused without pain, and the visual symptoms can be delayed for several hours.
Viewing the sun during a partial eclipse requires special eye protection, or indirect viewing methods.
Viewing the partial eclipse
The safest way to view the event is on the television or via live web viewings on the internet. Observing the eclipse directly through a telescope, binoculars or camera is not safe under any circumstances. Sunglasses and photographic film are also inadequate and should not be used to view the eclipse.
Only specially designed solar filters that are identified as suitable for direct viewing of the sun – bearing the CE mark and a statement that they conform to EC Directive 89/686/EEC – can be used to view the eclipse directly. Alternatively, a welder’s glass rated at No.14 or higher would be suitable.
Protecting your child’s eyes
It is dangerous to look at the sun at any time, and children may be tempted to sneak a peek during the eclipse. Children should be supervised carefully if they view the partial eclipse and they should be made aware of the dangers.
It is worth knowing that adult-sized special filter spectacles do not fit a child’s face and direct rays from the sun could easily damage the child’s eyes.
How to make a pinhole camera
An alternative and safe way to view the sun's disc is by indirect projection using a 'pinhole camera'. A perfectly adequate version can be made out of two thin, but stiff, pieces of white cardboard.
Punch a small, clean pinhole in one piece of cardboard. Do not make the pinhole too big or you will only have a shaft of sunlight rather than an image of the crescent sun. Stand with your back to the sun, holding up the piece of cardboard with the hole in it. Hold the other piece of cardboard as a 'screen' in your other hand and move it until an inverted image of the sun appears on it. To make the image sharper, move the screen closer to the pinhole.
Remember, do not look directly at the sun through the pinhole."