I like to think that vampires are just far more sensitive to UV light than humans. That way I can imagine them vacationing on the Riviera, tanning under moonlight.
I’ve never heard of moonburn, so it’s reasonable to assume that direct sunlight is required to harm them.
I always thought it was direct sunlight that burned vampires.
UVArrgghhh.
The light reflected from the Moon doesn’t feel (as) warm, while direct sunlight does (winters may be excluded).
They can’t be seen in a silver mirror which indicates their reflected light wavelengths go from 400 NM and below. Humans can see from to 380 NM to 700 NM . So, Clearly what kills them is their inability to discharge the visible light wavelengths energy fast enough, they overheat and then turn to dust as shown in Blade/JJBA/Underworld/Buffy/whatever
