Charon Texture

[FarGetaNik]

I am working on a texture for Charon, including some pre New Horizons data from mutual events (Hubble data showed no details on Charon). This is what I found:

charnmap.jpg (11.97 KiB) Viewed 3583 times

I wonder where the point is that faces Pluto. I'm getting very mixed results from research. John van Vliet's texture seems to be misaligned by 180° compared to Celestia'a default texture. The coordinate system of the image above also implies Celestia's default to be misaligned, but I also found maps with a coordinate system shifted by 180°.

[John Van Vliet]

it depends on the image and where it was posted
in the motherload add ons it is -180 to +180 ( all Mark buil at.el. start at 270 to 0 to 90 to 180 to 270 )

but most are using 0 to 360
until New Horizons images and the New prime-meridian

for the old Charon, i used this paper
http://iopscience.iop.org/article/10.1088/0004-6256/139/3/1128

this is -180 to 0 to +180

[FarGetaNik]

Now that New Horizons maps are all over the internet, it's hard to find the old telescopic maps at all. Oh so there are 2 definitions on the prime meridian, that explains my confusion. So the center, 0° of your texture is the point facing Pluto, right?