Permanent eye injury can occur instantly. Never look at the Sun through magnifying optics without a correctly designed, securely front-mounted, undamaged solar filter or a complete dedicated solar telescope system.
Filter the front aperture
For ordinary telescopes, binoculars, and camera lenses, the protective filter belongs securely over the front, before sunlight enters the optical system. Do not use old screw-in eyepiece “sun filters.” Do not improvise with sunglasses, smoked glass, exposed film, CDs, space blankets, or unverified material.
Inspect every time
- Check for pinholes, tears, scratches, loose cells, warped mounts, or missing parts.
- Remove or cap optical finders unless they are independently and correctly filtered.
- Secure filters so wind, children, or accidental contact cannot remove them.
- Supervise inexperienced observers continuously.
- Stop if any component, compatibility, or instruction is uncertain.
Dedicated hydrogen-alpha systems
Etalons and blocking filters are designed as complete systems. Do not mix blocking filters, energy-rejection components, or front and internal modules based on thread fit alone. Follow the manufacturer’s instructions for the exact model.
Trusted guidance
Use current American Astronomical Society solar-viewing guidance and trusted suppliers. Viewer certification statements printed on packaging are not, by themselves, proof that a product is safe.