Museum of Stars can be read when the protagonist spends time reading during his daily life. The book takes 1 chapter to complete. Upon reading the book, Ikebukuro will become accessible to visit. The book cannot be reread.
Ikebukuro is mostly known for its skyscrapers. I never realized they had a planetarium there... I guess they keep it exciting by doing things like hiring famous actors as tour guides. ...In any case, it's not the kind of place you'd visit alone. I recommend taking someone.
The planetarium in Ikebukuro is probably the closest one to here, so that's pretty convenient. It'd be fun to go with someone. Just don't fall asleep while they project the constellations, OK?