How close to the water can the light sit without a lid?

[jassz]

Rather than tell you something incorrect, I thought it would be best if I posted a thousand words with a picture or two. How do you tell if the endcaps are waterproof? Sorry, I bought this whole set up used, and it's my first tank so I don't know a lot of this stuff. Hanging it from the ceiling is a possibility in this spot, but I was worried it would swing too much, plus it's more difficult to remove to change bulbs etc.