Source: City of Splendors: Waterdeep
Your spells and spell-like abilities are tied to the phase of the moon, rising and falling with the strength of Selûne.
Prerequisite: Patron deity Selûne or Mystra, arcane or divine spellcaster level 1st.
Benefit: As shown in the table below, your effective caster level for all spells you cast or spell-like abilities you possess is tied to the phase of the moon.
For purposes of this feat, the new moon and full moon are considered to last three successive nights (the night before, the night of, and the night after the true full moon or new moon). Since Selûne's month is almost exactly as long as the calendar month, the moon is always full right at the beginning of the month, and dark right in the middle of the month, as shown below.
|Moon Phase||Days of the Month||Effective Caster Level|
|New Moon||15, 16 17||-1|
|Full||30, 1, 2||+1|