Sun filter foil for solar observing: AstroSolar has been in the market for more than 25 years and is the only protective film that does not impair the optical wave front, and enables it to be used at high levels of magnification without loss of sharpness or contrast!
The AstroSolar film is available as a single sheet of film, from which you can make your own filter for a telescope, spotting scope, camera or binoculars. However, the film is also used in the solar eclipse observing glasses.
The AstroSolar film has an optical density of 5.0 which is sufficient to protect the eye. For photographic applications it is also available with an optical density of 3.8. However, this film may only be used for photography!