Eyes first
The rule: filters on for every partial phase. Naked eyes only during totality itself. That is the entire rule, and it has no exceptions — not "just a quick glance", not through a phone screen, not at 99% coverage. At 99% the remaining 1% is still blinding.
Safe
- Eclipse glasses certified ISO 12312-2, undamaged, from a vetted supplier (AAS list).
- Handheld solar viewers with the same certification.
- Indirect projection: pinhole, colander, tree-leaf shadows — great for groups and kids.
- Front-mounted certified solar filters on cameras/binoculars/telescopes.
Never
- Sunglasses of any darkness, stacked or not. Smoked glass, film negatives, CDs, welding glass below shade 14.
- Any unfiltered camera, phone, binocular or telescope pointed at the Sun — and never glasses behind optics; the filter goes on the front.
- Damaged, scratched or unbranded filters.
During totality
When the last bead of sunlight vanishes, filters come off — totality is fully safe to watch and is the entire point of the trip. Know your local totality length (it varies from 1m39 to 6m22 on this path), set a timer for ~20 seconds before it ends, filters back on.
FAQ
When can I look without glasses?
Only during totality — the minutes when the Moon fully covers the Sun and the corona is visible. The instant a sliver of the bright surface returns, filters go back on. During every partial phase, before and after totality, direct viewing without an ISO 12312-2 filter can permanently damage your retina.
Are sunglasses, smoked glass or camera filters safe?
No. None of them. Only solar filters certified to ISO 12312-2 for eyes, and dedicated front-mounted solar filters for cameras, binoculars and telescopes. Never point unfiltered optics at the Sun — magnified sunlight destroys eyes faster than the naked view.
How do I check glasses are genuine?
Buy from vendors on the American Astronomical Society's vetted supplier list, check the ISO 12312-2 marking, and test: through real eclipse glasses you should see essentially nothing except the Sun itself.