Safe Viewing

We have sold out our supply of solar viewing glasses

Eclipse glassesIt is never safe to look directly at the Sun! Even for an instant. Do not look at the Sun through binoculars, a camera, or a telescope without purpose-built filters. Use your eclipse viewers, welders glasses that are rated at least #14, or project the image using a pinhole camera, for example.

Eclipse viewing glasses look like this, and are safe to use when viewing the Sun. While looking away from the Sun, put the glasses on, then look at the Sun through your glasses. Don’t remove the glasses until you are looking in a direction away from the Sun.

Are my glasses safe?

If the manufacturer went through the ISO certification process, the glasses would be stamped with something like 'ISO 12312-2 certified'. If they are not, they didn't go through the certification process, and they may or may not be safe as they haven't been tested. Unfortunately, some vendors have stamped their glasses with this even though they haven't been certified.

If you know what vendor you purchased them from, you could try look them up, the American Astronomical Society (AAS) has a list of vendors that are carefully checked.

The AAS page also talks in details about the safety, and while it is impossible without lab equipment to do a rigorous check, there are a few things you can do to check if they are NOT safe (this could be the case also if there is a scratch in an otherwise good pair of eclipse viewers):

You shouldn't be able to see anything through a safe solar filter except the Sun itself or something comparably bright, such as the Sun reflected in a mirror, a sunglint off shiny metal, the hot filament of an unfrosted incandescent light bulb, a bright halogen light bulb, a bright-white LED bulb (including the flashlight on your smartphone), a bare compact fluorescent (CFL) bulb, or an arc-welding torch. All such sources (except perhaps the welding torch) should appear quite dim through a solar viewer. If you can see shaded lamps or other common household light fixtures (not bare bulbs) of more ordinary brightness through your eclipse glasses or handheld viewer, and you're not sure the product came from a reputable vendor, it's no good. Safe solar filters produce a view of the Sun that is comfortably bright (like the full Moon), in focus, and surrounded by dark sky. If you glance at the Sun through your solar filter and find it uncomfortably bright, out of focus, and/or surrounded by a bright haze, it's no good.

A pinhole camera is a cheap and simple way to safely view the Sun. Here are some instructions: