astropy/astropy — pull request #368 by astrofrog (2012-08-30 09:00:24+00:00)
Title: Updated value of au constant to exact value adopted by IAU 2012 Resolution B2

I think resolution B2 of the IAU 2012 general assembly has been adopted. This defines the AU (or au) as an exact value in meters. This PR updates this, and also makes sure that pc and kpc are defined exactly too, based on the au. Is this the correct/exact definition of a parsec?