AbstractTotal solar eclipses are popular targets for amateur astronomers. At the same time, the eclipses are still scientifically important to observe the solar corona. Therefore, the eclipses are a good chance for amateurs to participate in scientific observations. In fact, some of amateur astronomers in Japan have been carried out scientific observations at the total solar eclipses collaborating with professional solar scientists over more than ten years. Some scientific results have been produced from the collaboration. We present here our collaborative activities as a practical example of citizen science.