I was looking into night vision equipment recently and found that some work with ultraviolet light. How much ultraviolet light is around at night? Is there enough ultraviolet light to see in the dark, without producing it? I don't care if it would be blurry, is it possible that there would be more ultraviolet light than visible light, even if it comes from artificial sources?

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    $\begingroup$ Night vision equipment that uses ultraviolet light as illumination is not a very good idea. Even near UV light has the ability to excite luminescence in many different (mostly organic) compounds. A UV night vision system would basically look like a night club with black light illumination. Do you mean infrared (IR) instead? $\endgroup$ – CuriousOne Oct 27 '15 at 8:24
  • $\begingroup$ I thought so too, until I looked it up. Funny thing is, when I was trying to find the page that said that to link here, I couldn't find that page, but I did find a different page that I hadn't seen before that answered this question, it said it needs an active illuminator. Still, how much UV light is around at night? Does it make sense to say that some of it sticks around by reflecting off of things? I'll edit the question to say this. $\endgroup$ – Chana Korenblit Oct 27 '15 at 22:44
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    $\begingroup$ I don't know enough about this to post an answer, but I can't think of any sources of UV at night other than what might reflect off of the moon. However, I wouldn't expect UV to reflect well from the moon, so my guess is that there's very little UV at night. $\endgroup$ – DanielSank Oct 27 '15 at 23:11

At night there is virtually no UV present. Most night vision devices work by amplifying low levels of ambient visible or near-IR light. Some (thermal vision devices) amplify long-wave IR emitted by normal temperature objects. In neither case is there enough UV to do any good.

Artificial lighting does not emit appreciable UV either - if it did it would pose a significant vision threat.


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