I was an amateur astronomer. I advise against the referenced Harbor Freight goggles. Here's reliable information about Welder's glass. - Herb https://www.harborfreight.com/ etc. Set comes with both flip front and permanent #10 lens.... https://www.space.com/36941-solar-eclipse-eye-protection-guide.html Welding goggles quote from Rick Fienberg, press officer for the American Astronomical Society (AAS), said "There is a particular circumstance in which [welding goggles are] safe," Fienberg said. "We don't recommend it because it's too easy to get the wrong kind of welding filter." Only goggles made for electric arc welding can be used to observe the sun, and they must have a shade scale number of 12 or higher. Shade 13 is ideal for solar viewing, but that shade is typically not sold in stores, Fienberg added. -------------------- https://eclipse2017.nasa.gov/safety Additional Safety Information Viewing with Protection -- Experts suggests that one widely available filter for safe solar viewing is welders glass of sufficiently high number. The only ones that are safe for direct viewing of the Sun with your eyes are those of Shade 12 or higher. These are much darker than the filters used for most kinds of welding. If you have an old welder's helmet around the house and are thinking of using it to view the Sun, make sure you know the filter's shade number. If it's less than 12 (and it probably is), don't even think about using it to look at the Sun. Many people find the Sun too bright even in a Shade 12 filter, and some find the Sun too dim in a Shade 14 filter — but Shade 13 filters are uncommon and can be hard to find. -- Herbert R. Johnson, New Jersey in the USA http://www.retrotechnology.com OR .net