A WARNING has gone out urging people to take safety precautions when viewing the partial solar eclipse this week.

It will start in Herefordshire at 8.23am and end at 10.38am on Friday (March 20) and will be the first eclipse since 1999.

Herefordshire Astronomical Society has produced a safe viewing guide to avoid people damaging their eyesight, warning people to never look at the sun without proper eye protection.

The sun should also not be viewed through sunglasses of any type – single or multiple pairs – or filters made of black and white or colour photographic film.

Other safety tips from the society are:

  • DON'T view the sun through any combination of photographic filters, crossed polarisers or gelatin filters, CDs, CD-ROMs, or smoked glass. These are NOT safe.
  • DO view the sun ONLY through special filters made for safe solar viewing, e.g. aluminised mylar filters, or black polymer filters, identified as suitable for direct viewing of the sun, bearing the CE mark AND a statement that it conforms to European Community Directive 89/686/EEC, or use welder's glass rated at no.14 or higher. Always read and follow the manufacturer's instructions carefully.
  • DO check filters thoroughly for any damage BEFORE use. DON'T use them if they are scuffed, scratched or there are pinholes in them
  • DON'T stare through the special filter for more than three minutes at a time. Intermittent use of the filter is the best way of viewing the sun.
  • If you use eclipse glasses DON'T ever use them to look at the sun through any optical instrument, e.g. telescope, binoculars or camera. Such devices concentrate the sun's harmful radiation and will cause severe eye damage or permanent blindness in a fraction of a second.
  • If you are not certain that a filter is approved and safe, or you have any other doubts, don't use it.

The society said that those without specialist equipment or eclipse glasses can view the sun by pin hole projection.

"Use a sheet of white paper or cardboard and make a small round and smooth pin hole," it said.

"Point this paper towards the sun but remember not to look at the sun directly.

"Hold another sheet of white paper or cardboard – to act as a screen – a small distance away and an image of the eclipse will be seen."

For more information on the Herefordshire Astronomical Society visit https://sites.google.com/site/hsastro/home