Looking at the spectrograph again, the simple lined image we have created from it is deleting some important data I believe. The center of the sphere shows a smaller round object in the center (A). The verticle and horizontal lines splitting the sphere do are not directly center of the smaller object in the middle (B). This object is the large crater on Merope 5C. With this information I think the directions are:
--| Go here (line to the crater)
-|| Honk probe with ADS
-|- Look to Horizon
|-- You will see something
I've ruled out the possibility of the -|- step being an orbit, as someone has already tried to honk a probe in orbit over the crater. No result
The symbol for the horizon is strikingly similar to all references of a horizon symbol and/or reference.
When trying to find a specific point of origin from the planet, the largest surface feature sure makes for a great reference point that is easily seen from orbit.
http://i.imgur.com/K0Q7KIb.gif