Tython Datacron Locations
There are 3 Datacrons on Tython. They are easy to get to.
Codex Entry - Galactic History 9: The Force Wars
The first Datacron is located in a cave near the Jedi Temple.
Codex Entry - Galactic History 10: The Tion Cluster
The second Datacron is located near the Ruins of Kaleth.
Coordinates: -641, -71
(Blue Matrix Shard)
Codex Entry - Galactic History 11: The Tionese Face the Hutt Empire
The third Datacron is located in the Forge Remnants.
Coordinates: -92, 920