Huh, according to this blog from 2013, it can be considered correct to refer to the currently illuminated pole of Pluto as positive, south, or north:Nitpicker wrote:I keep seeing references to Pluto's north pole on this illuminated side. I don't believe it is correct to call it the north pole. If Pluto were still considered a planet, the illuminated pole we see here, points comfortably below the ecliptic and invariable plane and so would be the south pole. And if considered a dwarf planet, the illuminated pole becomes the positive pole, via the right-hand rule.
(What a great image! But I'm surprised no one has complained that it is upside down.)
http://www.planetary.org/blogs/emily-la ... raphy.html
Love it!