You can easily unlock the Celestian form through meditation. There are no secret tricks. You should be able to do this. Unlocking the form also reveals additional events in the game, including events in the dark world.
So that's the problem, I can't open Celestia's form. When I talk to Kimiko, she keeps saying, "Bathe in our springs. Then come to me and we'll begin the meditation ritual." I don't understand what I'm doing wrong... I've been swimming in the springs for 65 days in a row and nothing happens.
I wrote to you on the official website in the "contacts" section.