Science, Technology, Engineering and Mathematics (STEM) play an important role in contemporary society and are vital to build the sustainable society of the future. However, STEM curricula do not seem very attractive to many students and increasing the level of achievement and interest in STEM is a priority in the context of the European Erasmus+ programme.In this project, we propose to use Astronomy as a possible entry point for Science education and as such consider Astronomy as a ‘gateway’ science to other STEM fields.Astronomy has a natural appeal to many as it focuses on the origin of the universe, galaxies, stars, planets and even life itself. Because of this appeal, astronomy can act as a ‘gateway science’ that opens a world of possibilities by nurturing inquisitiveness and the pursuit of knowledge using the scientific method. Moreover, as astronomical research is technology driven, astronomy education provides excellent opportunities to enhance different aspects of (integrated) STEM education and motivate (more) students to pursue their interests via higher education programs and STEM-oriented professional careers. As such, astronomy can play a crucial role in science and more general in STEM education.Although there seems to be something inherent in the subject of astronomy itself that appeals to many people, research shows that many of the astronomical phenomena are difficult to grasp and to teach. In this project, we will focus on optimising the teaching and learning potential of Planetariums on several specific astronomical concepts. Indeed, as visualising the (night) sky is one of the main goals of a planetarium, it might be a powerful setting to enhance student learning of the concepts that show to be difficult to understand deeply. Planetariums have indeed a long history in supporting astronomy interest, but the impact of the planetarium visits on the effective learning is vastly unexplored. There are still many questions about the role the unique visualisation possibilities in a dome can play in educating various kinds of audiences by not only fostering their interest in astronomy but also by preventing or remedying misconceptions about crucial notions of space and time, astrophysical phenomena and the universe as a whole.Our project aims at answering some of these questions by designing, testing and exchanging teaching/learning materials that support student understanding of crucial elements like spatial scales and time. Additionally, we will develop and exchange instruments to measure the learning outcomes that are obtained during planetarium visits, in order to support the design and validation process. The specific aspects of our focus are not only relevant for astronomy but a profound insight needs to be developed in these aspects for other sciences as well. Moreover, these concepts are fundamental in understanding the origin and position of planet Earth in the universe as a whole. By taking an international approach, carrying out research on students’ scientific thinking and testing the materials in diverse educational settings, with one university or science centre and one secondary school participating from each country, we will be able to identify essential elements for teaching/teaching learning materials, i.e. elements that are ‘universally’ important, independent of the local educational system. All outputs will build on original research and peer exchange, to maximise cross-country learning.The outputs of the project will include a better insight in students’ thinking on basic astronomical concepts and research based teaching/learning materials that support the learning of these concepts in the context of planetariums. Target public are secondary school students and their teachers.