Astronomical Observations at Nagashima-Aiseien, a Hansen’s disease sanatorium

Abstract

This paper presents the history and observational records of Nagashima Astronomical Observatory established in 1949 at Nagashima Aiseien, a national sana- torium for Hansen’s disease in Japan. The observatory was a part of the meteorologi- cal observatory of the sanatorium, and the observers, who were also Hansen’s disease patients, conducted regular sunspot observations and occasional stellar occultations. The observatory also provided residents and staff of the sanatorium with oppor- tunities to enjoy watching stars. Two astronomers outside the sanatorium deeply committed to the foundation and observations at the Nagashima Observatory: Issei Yamamoto, the first director of Kyoto University’s Kwasan Observatory, and Minoru Honda, known for his discoveries of comets and novas. The records of sunspot and oc- cultation observations were sent to Yamamoto as well as to the Tokyo Astronomical Observatory (Today’s National Astronomical Observatory of Japan) . The signifi- cance and uniqueness of the astronomical observations at Nagashima Observatory are discussed from the perspectives of amateur astronomy and the history of Hansen’s disease sanatoria.