Fought this worldboss with a pug ops group of 16 players levelled 33-38. It must be summoned by inspecting a clickable corpse at the extreme northwest edge of the map; it is located in the sub-zone directly north of the Sith starting area on Taris.
Some cursory notes about its abilities, for anyone that wants to attempt it:
The Ancient One (Level 38)
591,132 HP
Shockwave - Area attack that has a knockback component as well as damage. Interruptable.
Every now and then (every 10% or so), the Ancient One spawns non-elite worms adds that must be AoEd quickly. They often swarm the healers first, so any off-tanks and dps should be aware of that. Very simple fight otherwise.

coords: -750, -700 jedi corpse right click
drops: