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