Moonwatch Project


The International Geophysical Year (IGY) was intended to allow scientists from around the world to take part in a series of coordinated observations of various geophysical phenomena. In this project, the Smithsonian Astrophysical Observatory (SAO) in Cambridge, Massachusetts established a back-up network of volunteer visual observers called "Moonwatch" that would eventually involve thousands of amateur astronomers around the world. When the Soviet Union launched Sputnik 1 on October 4, 1957, SAO was one of the few agencies in the Western World ready to track the object. Going beyond the acquisition and tracking of satellites, SAO scientists used the observational data to determine variations in the density of the Earth's upper atmosphere through the observed effects of drag on satellites.

The Japan IGY Committee was the sponsoring agencies of the Japanese "Moonwatch" program. The supporting societies were the Astronomical Society of Japan, the Oriental Astronomical Association, the Japan Astronomical study Association, and Ikomasan Astronomical Society and so on. Three Japanese newspaper synicates, Mainichi Press, Osaka Yomiuri Press, and Tokyo Yomiuri Press, was the sponsors of Japanese Moonwatch effort, covering the cost of equipment for most of the station.
Over 79 Japanese teams were comprised with mainly college and high school students, averaging about 20 members in each. The leaders were generally experienced amateur and semi-professional astronomers. The stations were distributed among the main island of Japan, although somewhat more densely in the lower latitudes. They ranged from N32 degree to N44 degree.

In Seikei, Mr. Tokichi KATO, the head of SMO, organized students team for the visual satellite observation. This team was called "Musashino Moonwatch Team".
On October 5,1957, the Soviet Union launced the first artificail satellite, "Sputnik 1"(1957a). Mr. Kato and his team prepared to observation, On October 14th, a student found the satellite at low in the north-northeastern sky. This was the first observation at Tokyo, however, he could not measure its orbit. The first satellite track data were obtained on the morning of Oct 15. The main body of Sputnik 1, the rocket, and the cap of rocket, were observed in the nortern sky.

The first data of Sputonik 1
satellite Direction Height Local Time (JST) Magnitude Course
Rocket (a1) N54E 27 4 h 46 m 13.0 s 2 from Saharin to Nemuro( Hokkaido)
Cap N 13 4 h 48 m 13.8 s 5 500 km height
Sputnik 1(a2) N 11 4 h 52 m 04.5 s
Photograph showing observation Arrangement of the elbow type telescope

From 1957 to 1962, the Musashino Moonwatch team observed 403 times, and succeeded 225 times to catch the artificail satellites. And a total of 3305 students were involved in project. The U.S. National Academy of Science (NAS) and the Smithonian Astronomical Observatory, commended the Seikei team for their effort.

Certificate of commendation from NAS Certificate of commendation from SAO