You detect psionic auras. The amount of information revealed depends on how long you study a particular area or subject:

1st Round: Presence or absence of psionic auras.

2nd Round: Number of different psionic auras and the strength of the strongest aura. An overwhelming aura stuns you for one round and the spell ends.

3rd Round: The strength and location of each aura. If the items or creatures bearing the auras are in line of sight, you can make Spellcraft skill checks to determine the psionic discipline involved in each. (Make one check per aura; DC 15 + power level, or 15 + half caster level for a nonpower effect.) 

Psionic areas, multiple types of psionics, or strong local psionic emanations may confuse or conceal weaker auras.

Aura Strength: An aura’s psionic power and strength depend on a powerl’s functioning power level or an item’s manifester level.
 

If an aura falls into more than one category, detect psionics indicates the stronger of the two.

Time Aura Lingers: How long the aura lingers depends on its original strength:
 

Note: Each round, you can turn to detect things in a new area. You can tell the difference between magical and psionic auras. The spell can penetrate barriers, but 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt blocks it.

Campaign lore: This spell was given to Souriin by Athalar. The spell has recently been added to the "compulsory learning" category at the University of Craft and Thought. Rumour in Béray is that detect psionics is also circulating widely in Sunhaven, despite that nations' complete ban on all magic not emanting from the Sun God.