Since I'm in Missouri and have the eclipse coming up I decided to buy some Galileo G-SFB70 solar filters for my Barksa 15x70's. They arrived UPS today and I put them on my binoculars. They actually fit pretty well. I rolled back the rubber casing, put the filters on the front and rolled the rubber casing up over them making for a pretty tight fit.
How do I tell if these filters are good?
The fit is tight. I might even tape them on when in use.
When looking through the binoculars with the filters installed at the brightest lights in my home I have to wait for my pupils to dilate before I can see any light at all.
Is there any official way to test them?
If they were bad what are the signs?