Mihoshi Akeno  

Hoshimi-chan, Mii-chan, 明野 美星

Mihoshi is a lively young lady who is slightly older than Saku but exhibits childish behavior on occasion. Her fascination for the cosmos stems from her father, and she enjoys spending time outdoors gazing at the stars or engaging in other activities. Though Saku may not always be enthusiastic about joining her, Mihoshi convinces him to become a member of their school's astronomy club.