We present the Stargazing Live! program comprising a planetarium experience and supporting lesson activities for pre-university physics education. The mobile planetarium aims to inspire and motivate learners using real telescope data during the experience. Learners then consolidate their learning by creating conceptual models in the DynaLearn software. During development of the program, content experts and stakeholders were consulted. Three conceptual model lesson activities have been created: star properties, star states and the fusion-gravity balance. The present paper evaluates the planetarium experience plus the star properties lesson activity in nine grade 11 and 12 classes across three secondary schools in the Netherlands. Learners are very positive about the planetarium experience, but they are less able to link the topics in the planetarium to the curriculum. The conceptual modelling activity improves the learners understanding of the causal relationship between the various stellar properties. Future work includes classroom testing of the star states and fusion-gravity balance lessons.