“Along an inlet through the moon” skyshard is located on a small island, with palm trees. It can be easily spot, since there are no large rocks or any other huge obstacles that can block your view of the skyshard. You can spot it from the eastern Khenarthi’s Roost’s shore without problems. There are no important POIs nearby, and only explorers will discover this shard.
In the Western Khenarthi’s Roost. Go to the west from Temple of the Dark Moon (eye icon).