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That is horrific and likely dangerous "advice". The mylar composite used in floppy disks seems opaque... to visible light. 54% of the Sun's energy output is

That is horrific and likely dangerous "advice". The mylar composite used in floppy disks seems opaque... to visible light. 54% of the Sun's energy output is in other wavelengths. There is no certification that a floppy disk cookie will block those. Plus it has a big hole in the middle, danger of inadvertent viewing. This is like the argument I have with other photographers every eclipse when they try to use their 'super-dark' neutral-density filters. Sure they block ten stops of light, but the IR and UV just sails on through. Unless it's designed and certifed as a Solar viewing material just don't even contemplate it. You're better watching the eclipse on TV in that case.

scotty79 9y ago
Does eye lens focus UV an IR? Or is the amount that goes through the hole of the size of iris enough to do the damage unfocused?
raverbashing 9y ago
> Unless it's designed and certifed as a Solar viewing material just don't even contemplate it. People have been using dark pieces of photographic film to see eclipses since ever. I wonder if there has been studies on its UV transmissibility Thought you're right about the super-dark film and I don't think those are dark enough even on the visible range Though I do agree if you want to stare at it directly your best choice is to get solar viewing glasses (preferably not a fake one) This page has some tests: astronexus.com/gatfaq/solar-filters besides poor optical quality floppy disks allow wavelenghts > 800nm to pass (this is IR range) A good suggestion that seems easy to obtain: welder's glass
- 4ad 9y ago
  > People have been using dark pieces of photographic film to see eclipses since ever. Fully exposed and developed black and white film is safe, color negative film, however, is totally unsafe, regardless of how dark it might seem. The film has to contain real silver particles, not color dyes. Beware of monochromatic film that looks black and white but it’s really a color negative film developed using C41 process. It has to be real black and white film. http://www.mreclipse.com/Totality2/TotalityCh11.html#Film http://www.mreclipse.com/Totality2/TotalityCh11.html#Film https://eclipse.gsfc.nasa.gov/SEhelp/safety.html https://eclipse.gsfc.nasa.gov/SEhelp/safety.html

scotty79 9y ago

Does eye lens focus UV an IR? Or is the amount that goes through the hole of the size of iris enough to do the damage unfocused?

raverbashing 9y ago

> Unless it's designed and certifed as a Solar viewing material just don't even contemplate it. People have been using dark pieces of photographic film to see eclipses since ever. I wonder if there has been studies on its UV transmissibility Thought you're right about the super-dark film and I don't think those are dark enough even on the visible range Though I do agree if you want to stare at it directly your best choice is to get solar viewing glasses (preferably not a fake one) This page has some tests: astronexus.com/gatfaq/solar-filters besides poor optical quality floppy disks allow wavelenghts > 800nm to pass (this is IR range) A good suggestion that seems easy to obtain: welder's glass

4ad 9y ago
> People have been using dark pieces of photographic film to see eclipses since ever. Fully exposed and developed black and white film is safe, color negative film, however, is totally unsafe, regardless of how dark it might seem. The film has to contain real silver particles, not color dyes. Beware of monochromatic film that looks black and white but it’s really a color negative film developed using C41 process. It has to be real black and white film. http://www.mreclipse.com/Totality2/TotalityCh11.html#Film http://www.mreclipse.com/Totality2/TotalityCh11.html#Film https://eclipse.gsfc.nasa.gov/SEhelp/safety.html https://eclipse.gsfc.nasa.gov/SEhelp/safety.html