Here is the full list of all 20 Star Sky 3 achievements.
They Meet at Last
Path to the Waking World
It is uncovered
Together forever
Dark turned to light
Use it well
Release it
She is watching
The guardian
Water or not
A beautiful thing
A trait passed on
Where they roam
Free at last
They are precious
A magic gift
Being friendly
Friendship
Grow more
Fruit from the tree