Reading the catalogue
Reading the catalogue
Solar retinopathy is painless while it happens and can be permanent. There is no warning sensation to rely on, which is why every rule below is written to be safe when you are not certain rather than correct when you are.
Outside the path of totality there is no moment during a solar eclipse when it is safe to look at the sun without a solar filter. A partial eclipse is still the sun.
Inside the path, totality itself is the exception — and if you cannot say with certainty that you are inside the path and that totality has begun, then for you the exception does not apply. The instant any part of the sun’s disc returns, the filter goes back on.
This page cites no regulator. Before an eclipse, read the current guidance from Health Canada and from an astronomical society covering your region, and follow that.
Inspect the filter before every use: hold it up to a bright lamp and look for scratches, pinholes, creases, or any place the filter has come away from the frame. Anything wrong with it means it goes in the bin, not on a face.
Put the filter on before you look up, and look away before you take it off.
Supervise children the whole time. A card frame slips easily, and the instinct to peek around it is strong.
Check a filter you have kept from a previous eclipse as though it were new. Storage damage is the common failure.
Sunglasses, however dark, and however many pairs are stacked.
Smoked glass, exposed film, floppy disks, welding glass of unknown shade, or anything improvised.
A camera, phone, telescope, binoculars or finderscope used while wearing a viewer. Concentrated sunlight will destroy the filter and your sight in the same instant. Optics need their own front-mounted solar filter.
A filter that is scratched, punctured, creased, or separating from its frame.
ISO 12312-2:2015 is the international standard covering filters intended for direct observation of the sun. It is a testable property of a particular filter made by a particular manufacturer and verified against a particular report — not a label a shop can apply to itself, and not something a printed frame can prove.
Ask any seller, including this one, for the following before you buy. A seller who has the record will hand it over.
The manufacturer's legal name
The filter model or material designation
The laboratory that tested it, and that laboratory's accreditation
The test report number and its date
The production lot the pair in your hand belongs to
This site publishes none of it yet, for any listing. That is stated on every listing page and in the homepage register, and it is the reason no product here is described as certified.