The problem of this study was to measure the effects of differing curricular patterns involving the use of planetarium centered activities on the affective domain of high-,middle-, and low-achieving secondary school students. Two different curricular patterns were studied. At each achievement level, one group viewed two planetarium lessons in conjunction with their classroom work in astronomy. Also, at each achievement level, two groups viewed the planetarium lessons as review activities which followed their completion of classroom work in astronomy earlier in the school year. The following conclusions were made with respect to the planetarium-related curricula studied. 1. Two exposures to planetarium lessons as a review activity caused a significant decline in the attitude toward astronomy among high-achieving students. 2. Two exposures to planetarium lessons did not significantly improve students' attitudes toward astronomy at any achievement level or with either curricular pattern studied. 3. Middle- and low-achieving students' attitudes were not significantly affected by two exposures to the planetarium lessons. Varying the manner of employing the planetarium in relation to classroom work in astronomy, in the manner studied, made no significant differences in the attitudes of students at either of these achievement levels.