Ultravision

By means of this spell the magic-user empowers the recipient to see radiation in the ultraviolet spectrum. 

In night conditions this means that vision will be clear, as if it were daylight, to a range of 100 yards, and shadowy and indistinct from beyond 100 yards to about 300 yards distance. If the night is very dark, with thick clouds overhead, reduction of ultravisual sight is 50%.

Where more than about 6 feet of earth or 3 feet of stone interpose between the sky and the individual, such as in virtually any underground area, ultravision allows only vision of the dimmest sort in about a 3-foot radius, since the ultraviolet rays are screened out. (Of course, if an emission source is nearby, the visual capabilities improve accordingly.) 

Nearby light, including the radiance shed by magic items, tends to spoil ultravision, the brightness of the rays "blinding" the eyes to dimmer areas more distant. 

The material component for this spell is a crushed amethyst of at least 500 gp value.

Except as noted above, this spell is essentially the same as the 4th-level magic-user spell of the same name.

Note additionally that creatures with high Intelligence might be able to detect invisible creatures by the use of ultravision, either natural or magically bestowed. 

The required material component for the illusionist version of this spell is a powdered essence of carrots.