Wrath or Starfire during Celestial Alignment ?

[lymf]

And also toughts on moon and sunfiering ads that will die before the full duration of them

[earthwormjim]

Starfire is stronger, use it.

Unless you're only going to get a handful of ticks, multi-dot. Probably breaks even if the mobs will last through 3 ticks or so, and that's extra chances for a starsurge proc.