Planetarium Ghost Travel: The Collected Works Of Sakatsuki Sakana summary:

A combination illustration and manga artbook featuring the ultramarine works and fantastical world of Sakatsuki Sakana. ---The few short manga stories included are a side stories that served as a precursor to Sakatsuki's eventual ongoing publication (https://mangadex.org/title/77c7d3eb-16e9-4ef2-81f0-4d3876a037c5/star-tripper-planetarium-ghost-travel). They are irrelevant to the main storyline, but follow 303's solo travels around Sakatsuki's starry universe.- 3.1 - Prologue- 3.2 - Listening to the Rain- 3.3 - Buying Sweets- 3.4 - Drinking Kikiriri- 3.5 - Seeing Space Fashion- 3.6 - Climbing the Tower- 3.7 - Making A Guess- 3.8 - Epilogue