Let's be honest – summers in Japan can be scorching hot with high humidity, making outdoor activities just about unbearable at times. Indoor events provide some respite from the sweltering heat, and a fun festival taking place at the Konica Minolta Planetaria Tokyo provides the atmosphere of a summer matsuri without the stifling conditions.
The Starry Sky Summer Festival runs from the beginning of August until late September, and is set to include fun "fireworks" displays in the planetarium dome, limited-time food and drink menus, and fun summer festival games (additional fees are required for these).
Please note if you plan to visit that the festival activities conclude at 4pm on Fridays during the period, and there are no festival events on Saturdays.