Ordinarily "Commune" costs 500gp to cast, however am I right in saying that an Oracle with this revelation (Heavens) can do it once per day at no cost?
Star Chart (Ex): Your copious notes contain a working model of the night sky expressed in artistic scribbles and arcane mathematical formulae. Once per day, you may spend 10 minutes contemplating your star chart to gain the benefit of the spell commune. You must be at least 7th level to select this revelation.
Seems pretty good to me :-)
Incidentally, anyone care to express an opinion on how this clause from the Commune spell should be interpreted in this case:
The answers given are correct within the limits of the entity's knowledge. “Unclear” is a legitimate answer, because powerful beings of the Outer Planes are not necessarily omniscient.