On August 5 (Mon.) and 6 (Tue.), 2024, we held an astronomy training for students from Kariya High School in Aichi Prefecture and Matsumoto-Fukashi High School in Nagano Prefecture. The students observed a sample of Ryugu and took a class about results of Hayabusa2 mission. They estimated the distance to galaxies from photographs of galaxies and used the recession speeds of these galaxies to determine the age of the universe.