Here is an engaging way to help your students explore how concave and convex lenses refract light to produce real and virtual images. Students measure the lenses' focal lengths and discover how lens pairs can be used to make 2 different types of refracting telescopes. From the determined focal lengths, students calculate their telescopes' magnification powers. Kit includes instructions, activities, and materials to build 8 hand-held refracting telescopes (4 Galilean and 4 Keplerian), each with a 444-mm-focal-length objective lens and a 50- or 150-mm-focal-length eyepiece lens.