The purpose of this study was to provide an online astronomy activity using the Stellarium program as a virtual planetarium. The implementation was conducted with 30 preservice primary school teachers (PPTs) who participated in a non-formal workshop that included interactive, technology-based astronomy practices embedded with the "R"elate, "E"ngage, "A"pplying, "C"ooperating, "T"ransferring strategy. The activity featured in the implementation covers the zodiac constellations and common related misconceptions, the duration of the Sun in the constellations, and the concepts of astronomy, astrology, and star clusters. At the end of the implementation, an online-survey was conducted to elicit feedback from the PPTs. According to the results of this study, PPTs enjoyed using Stellarium as a virtual planetarium. The PPTs were aware of certain astronomical concepts and misconceptions, stated that the activity content related to daily life, and that they gained skills related to astronomy teaching. The PPTs reported being satisfied with working in groups, and actively communicating actively with their peers. They suggested adding mythological stories while teaching the constellations. In addition, they proposed increased preliminary preparation and practice prior to the activity so as to gain basic pre-skills in using a virtual environment.