...I haven't tried that yet. I assume with good quality binoculars.. 

Yes, is a filter for each camera. 

No it does not, it keeps the city lights or the light the eminates from populated areas from getting in. So you get a clearer picture of stars, I used it a few times and it works but if you live in a heavy light polluted area it may not make much difference. 

If you can fit a 67 mm UV filter on the end of lens this should work without touching the glass. You could get the 82mm version and use a stop down adapter. 

LPRs are designed to filter both mercury vapor and sodium spectral lines. I cannot answer via personal observation how good of a job it filters Mercury Vapor as my city phased those out long ago. Of note, I would classify this filter as a broadband filter, if you have a higher amount of light pollution you might opt for a narrowband or line filter instead to see better results.