The Department of Health has published an Eclipse Safety Code ahead of this week's partial eclipse of the sun.
On March 29 between approximately 10.45am and 12.25pm the moon will pass across the face of the sun.
Children in particular should be made aware of the dangers according to the DoH statement. In October 2005, a young boy suffered loss of central vision after looking directly at the sun during a partial eclipse.
The absence of pain or discomfort while looking at an eclipse with the naked eye or through some makeshift protective system does not mean damage to the eyes will not occur. Permanent damage to the retina can occur 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.
Sunglasses are not safe, since they do not block the harmful and invisible infrared radiation which causes retinal damage.
Only properly designed and certified solar filters should ever be used for direct viewing of the sun, identified as suitable for direct viewing of the sun, bearing the CE mark and a statement that it conforms to EC Directive 89/686/EEC, or use a welder’s glass rated at No 14 or higher.
Often special filter spectacles being adult sized do not fit a child’s face and direct rays from the sun could easily damage the child’s eyes. Please ensure children are supervised carefully if they are allowed to view the partial eclipse as a formal exercise.
The safest way to view the sun 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 and let the sunlight fall through that hole onto the second piece of cardboard, which serves as a screen, held below it.
- An inverted image of the sun is formed. To make the image brighter, move the screen closer to the pinhole. Do not make the pinhole wide or you will only have a shaft of sunlight rather than an image of the crescent sun.
- Remember, this instrument is used with your back to the sun. The sunlight passes over your shoulder, through the pinhole and forms an image on the cardboard screen, beneath it. Do not look through the pinhole at the sun.
This guidance is issued by the Department of Health and has the support of the Royal Astronomical Society and the Royal College of Ophthalmologists
