Watching Wednesday's solar eclipse? The glasses you need to protect your eyes

Rochdale is preparing for one of the most spectacular astronomical events visible from Britain in years, with a major partial solar eclipse due to darken the skies on Wednesday 12 August.

But anyone planning to look up needs to get one thing sorted before Wednesday evening: ordinary sunglasses are not safe for watching a solar eclipse.

Specialist solar-eclipse glasses are designed to reduce the Sun's radiation to a level suitable for direct viewing. The important marking to look for is ISO 12312-2, the international safety standard covering filters used for direct observation of the Sun.

The Royal Observatory Greenwich advises eclipse watchers to use purpose-made solar viewing protection. Eclipse glasses should be inspected before use and should not be used if the filter is scratched, torn, punctured or otherwise damaged.

WHAT SHOULD YOU BUY?

Rochdale Daily has found Astral Solar Eclipse Paper Glasses from Absolute Eclipse, designed specifically for direct solar viewing. The retailer states that the glasses comply with EN ISO 12312-2:2015 and use specialist solar-filter material.

Single pairs are advertised at approximately £4.30 based on the retailer's euro price and current exchange rates, although the exact sterling amount charged may vary with the exchange rate and payment provider. Multipacks are also available for families and groups.

BUY ASTRAL SOLAR ECLIPSE GLASSES: https://absoluteeclipse.eu/products/astral-solar-eclipse-paper-glasses?sca_ref=12037834.ocoapNfFOz&sca_source=Rochdaledaily

Rochdale Daily may receive a commission if readers purchase through the link above. This does not increase the price paid by the customer.

WHY AREN'T SUNGLASSES ENOUGH?

Even extremely dark conventional sunglasses are designed for everyday daylight, not staring directly at the Sun. During an eclipse, the reduction in visible daylight can also create a false sense that looking towards the Sun has become safer. It has not.

Looking directly at the Sun without appropriate protection can damage the retina at the back of the eye. Crucially, retinal injury may occur without immediate pain, meaning somebody may not realise damage has occurred while they are watching.

Purpose-made eclipse glasses meeting the appropriate solar-viewing standard or an indirect viewing method such as a pinhole projector should therefore be used.

CHECK YOUR GLASSES BEFORE PUTTING THEM ON

Before Wednesday's eclipse, check the solar-filter material carefully. If you find scratches, holes, tears, punctures or other damage, do not use that pair.

Put your eclipse glasses on before looking towards the Sun and turn away from the Sun before removing them. Children should be supervised to make sure the glasses remain correctly positioned while they are looking upwards.

There is another important distinction: eclipse glasses are intended for unaided viewing with your eyes. They should not be used to look through binoculars, telescopes or camera lenses. Optical equipment concentrates sunlight and requires correctly fitted specialist solar filters designed for that equipment.

WHAT IF YOU CAN'T GET GLASSES IN TIME?

You can still experience the eclipse without looking directly at the Sun. A simple pinhole projector allows sunlight to pass through a small opening and project an image of the partially eclipsed Sun onto another surface.

Whatever method you choose, do not improvise with ordinary sunglasses, tinted glass or homemade eye filters.

WHEN CAN ROCHDALE SEE IT?

The eclipse takes place on Wednesday 12 August, beginning in the early evening and reaching maximum coverage shortly after 7pm in the Greater Manchester area. Around nine-tenths of the Sun is expected to be obscured at maximum, weather permitting.

It should create an extraordinary sight across Rochdale - but the most important preparation is making sure everyone watching has suitable eye protection before looking towards the Sun.