Insomniacs After School, Vol. 1 (manga)

Two sleepless teenagers find kinship as they escape to their school's astronomy observatory. Unable to sleep at night, Ganta Nakami is cranky in class and unpopular with his classmates. He discovers that the school observatory, once used by the now-defunct astronomy club, may be the perfect place for a nap-but he's not alone.

Fellow insomniac Isaki Magari is willing to share the observatory with Nakami, and a friendship between the two begins as they bond over the most unlikely of things. Dark rumors about what befell the members of the astronomy club keep people away from the school observatory, and that's what makes it the perfect sanctuary for Nakami and Magari to get some much-needed rest. Unfortunately, the school faculty can't allow its unsanctioned use.

But if there were a new astronomy club, maybe these two insomniacs could have a place to call home!