The cultural festival begins, though initially no one is coming to see the planetarium. After Haruko from the city planetarium arrives, she helps to bring in the people and the planetarium is well received by viewers for the rest of the day. Mihoshi thanks Saku for everything he has done for the club and is thankful that she has not caused him any trouble while he was helping the literature club. After the festival, the club members are distraught at the thought of dismantling the planetarium, but eventually take it down. The astronomy club was not able to win any prizes for the festival and thus still do not have enough money to even buy a telescope. Sayo takes the club to her family's Buddhist temple and perform a small moon festival. The astronomy club receives a video letter from the president of the astronomy club of Nogishiro High School in the same prefecture as Sōei High School inviting the club to the Autumn Stargazing Conference of the Prefectural High School Astronomy Network.

Mihoshi and the other members are excited about the Autumn Stargazing Conference, and are surprised at the size of Nogishiro High School along with the number of members in their astronomy club. After the sun sets, everyone splits into groups and the process is explained by Nogishiro's astronomy club president Ayumi Ōmi; each group is free to stargaze until the moon sets, upon which each group will begin counting visible stars in a patch of sky to measure the overall brightness of the sky. Ayumi asks Saku to help on patrol around the school and they come across Hime and a second-year named Musa after she overreacts and thought he was trying to assault her. Afterwards, everyone goes back to the roof now that the moon has has set, and Ayumi confesses to Saku that her astronomy club actually only has nine members in it and mostly everyone else is from other clubs. Takeyasu Roma does a narration of the autumn sky myth which everyone loves. Ayumi later confronts Roma and reminds him that they were once members of the same astronomy club at Goshima Science Museum.

The astronomy club members wake up late the next morning and first spend some time warming up in the outdoor baths. Ayumi Omi notices Roma stressing over studying for university entrance exams, and takes him to buy a study book and then have dinner at a fancy restaurant. The astronomy club members wait until the moon sets on the third night and spend their final night in the mountains stargazing and taking photos. The members use some eyepieces Mihoshi brought to find Saturn, which is an entrancing sight for everyone. The following spring, Mihoshi has succeeded as club president after Roma graduated and entered into university with Ayumi. Everyone puts in more effort this year for recruiting members, since they are now one member short, and are again in danger of getting disbanded.

DVD 5 Special.