Here is the full list of all 21 planetarian HD achievements.
Completed planetarian ~the reverie of a little planet~
Used the Music Mode
Used the CG Mode
Finished Chapter 16, "Yumemi's Prayer"
Finished Chapter 15, "A Holographic Reflection"
Finished Chapter 14, "At the End of the Battle"
Finished Chapter 13, "The Battle Against the Fiddler Crab"
Finished Chapter 12, "At the Rift in the Quarantine Wall"
Finished Chapter 5, "The Junker's Reverie 2 / Light Bulbs"
Finished Chapter 11, "The City 2 (Drunk with Alcohol and Rain)"
Finished Chapter 10, "The City 1 (The Abandoned Streets)"
Finished Chapter 9, "Leaving the Planetarium Behind"
Finished Chapter 8, "The Reverie of Mankind Spreading its Wings"
Finished Chapter 7, "Yumemi's Projection"
Finished Chapter 6, "The End of Repairs / Before the Projection"
Finished Chapter 4, "Repairing the Projector"
Started planetarian for the first time
Read the Opening
Finished Chapter 1, "The Robot's Bouquet"
Finished Chapter 2, "The Sealed City and the Junker"
Finished Chapter 3, "The Junker's Reverie 1 / At Reception"