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