Ooh! How fascinating!

I especially like Alisa's, for both the scientific reason, and the fact I am indeed English!

It is true that cameras can pick up inferred light, whilst our eyes aren't equip to pick up the frequency. The mechanical ability to pick up all light, and the organic inability to react to light above a certain wavelength.

I was thinking about how they would cloak such a craft, when the idea came to me. It was so simple! I cried out in my mind. The abuse of Red Shift.

Red Shift is the process when optical radiation - I.e. light - stretches and changes frequency over a distance due to the stretch of the light-waves. Whilst Red-shift is too high for us to see, Blue-shift is too low, travelling into the ultraviolet spectrum. What if the owner of the UFO had developed the technology to make the light rebounding off the craft travel further then it physically is? Via micro-particle refraction, or black-matter distortion(Which is essentially the same thing), if they could get the light to travel so far, it shifted frequencies into the inferred spectrum, then no one would be able to see it unless seen through an inferred-capable device!