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
Grow more
Dark turned to light
She is watching
The guardian
Use it well
Release it
Water or not
A beautiful thing
A trait passed on
Being friendly
A magic gift
Where they roam
Free at last
Fruit from the tree
Friendship
They are precious