AbstractOf the 1100 planetariums in the U.S., approximately 96% are smaller facilities. The majority of these use a program type called the “Star Show”, whereas some have advocated a different type called the “Participatory Oriented Planetarium.” The purpose of this study was to investigate the following question: “In a smaller educational planetarium, with a capacity of between 15–75 people, is a traditional ‘Star Show’ planetarium program, or a ‘Participatory Oriented Planetarium’ program the most effective method of instruction and attitude change?” A large scale investigation was conducted in Pennsylvania, with four smaller replications in Texas, Minnesota, California, and Nevada. In each planetarium, a group of 8–10 year old students were identified and randomly assigned to groups. 556 students were tested. The testing instruments included a paper‐and‐pencil content test and a Likert‐style science opinionnaire. The instructional programs were chosen from existing scripts to avoid bias in their construction. Both programs dealt with constellation study. Correlatedttests were used to compare pretest to posttest scores and two‐way factorial analyses of variance were used to compare the groups' posttest scores. It was concluded that, “The Participatory Oriented Planetarium program, utilizing an activity‐based format and extensive verbal interaction, is clearly the more effective utilization of a small planetarium facility for teaching constellation study and possibly for improving students' attitudes tow