Update: this first sentence is Wrong: Those are pretty expensive at the moment. You can use Welder's Goggles with a #14 shade [1]. Most welding supplies stores

Update: this first sentence is Wrong: Those are pretty expensive at the moment. You can use Welder's Goggles with a #14 shade [1]. Most welding supplies stores will not have anything that dark, but if you get a set which allows insertion of extra lenses, you can get it dark enough. As a bonus, googles like these will fit over prescription glasses, and also block light from the sides. Try it out before the eclipse! If you think "this is a bit bright but it's tolerable" then you need something darker. You don't need the sun to look bright at all through the glass -- it just needs to be visible so you can see the shape. [1] https://eclipse.gsfc.nasa.gov/SEhelp/safety.html https://eclipse.gsfc.nasa.gov/SEhelp/safety.html