Astronomy is one of the most popular of the sciences. That this is so can be seen in the frequent news articles about astronomical discoveries and happenings, in the number of questions about the sky fielded by planetarium and observatory staff, and in the large turnouts for public observing sessions at observatories or astronomy club star parties.

Another reflection of astronomy’s popularity is the fact that thousands of university students study the subject each year. Only a few of these are training to become professional astronomers. The vast majority of these students seek mainly to obtain a general background. An important subset of the latter group are those students preparing to teach in the schools and who have the need to understand, and be able to explain, common astronomical phenomena clearly. Those of us who teach introductory astronomy courses have an obligation to ensure that these prospective teachers are well trained.