The rule that matters most
Looking directly at the uneclipsed or partially eclipsed Sun can injure the retina without immediate pain. Ordinary sunglasses, smoked glass, camera filters and improvised materials do not make direct viewing safe.
Use eclipse viewers that comply with the ISO 12312-2 standard and come from a traceable supplier. Inspect them before every use. If the film is scratched, punctured, detached or unusually bright, discard the viewer.
How to use eclipse glasses
- Stand still and look away from the Sun before putting the viewer on.
- Cover both eyes completely, then look at the Sun through the filter.
- Look away again before removing the glasses.
- Supervise children and make sure the viewer fits securely.
- Never combine eclipse glasses with binoculars, a telescope or a camera lens unless the optical device has its own front-mounted solar filter.
Totality is the single exception
During a total solar eclipse, filters may be removed only after the bright photosphere has disappeared completely and totality has begun at your location. Put them back on as soon as the first bright point of sunlight reappears.
This exception does not apply to partial or annular eclipses. In an annular eclipse a brilliant ring of sunlight remains visible throughout, so certified protection is required for the entire event.
Safe alternatives for groups
Projection is excellent for classrooms and families. A pinhole projector, colander or telescope projection setup forms an image of the Sun on a surface, allowing several people to observe without looking toward the Sun.
Never look through the pinhole, binoculars or telescope while projecting. Optical instruments concentrate solar energy and require equipment-specific procedures led by an experienced operator.
Scientific references
References used for eclipse dates, safety guidance and local calculations.