The present research investigates the perceptions of kindergarten students, and pre-service teachers from the Early Childhood Education Department at the University of Athens, concerning the frequency of the Moon's appearance in the night sky. ?he sample consisted of 15 people from each population group. Semi-structured interviews were conducted to collect the data. Data analysis suggests that the vast majority of both population groups consider the presence of the Moon in the celestial dome to be indicative of the night. Furthermore, when the relevant questions are asked independent of the need to explain other phenomena, the participants usually respond with the tautological statement that they can always see the Moon at night because it is night. The research also revealed that although knowledge which is acquired over time from: (a) observational data (e.g. the periodicity of the Moon's Apparent Motion is not 24 h), and (b) school/extracurricular activities (e.g. the Moon orbits the Earth with a frequency that is not 24 h) constitutes grounds for doubting the belief that the Moon is always visible in the night sky, it does not actually affect this belief.