I work with infrared lasers, and the main safety advice I will give you is that 850nm light will look very dim, even if it is very bright. So be careful about shining it in your eyes, because how bright it looks is misleading. That said, it does take a very bright source of visible or IR light to actually damage your eyes.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
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