How to Make a Simple Telescope from Household Items

Build a working telescope using cardboard tubes, magnifying glasses, and basic household materials for stargazing fun.

  1. Gather Your Materials. You'll need two cardboard tubes of different sizes (like a paper towel tube and a toilet paper tube, or mailing tubes), two magnifying glasses with different magnification powers, scissors, tape or glue, black construction paper or paint, and a ruler. The key is finding tubes where one fits snugly inside the other. If you don't have magnifying glasses, you can often find inexpensive ones at dollar stores or use reading glasses from the pharmacy.
  2. Prepare the Tubes. Cut the larger tube to about 12-14 inches long and the smaller tube to about 8-10 inches. The smaller tube should slide smoothly in and out of the larger one - this sliding motion will help you focus your telescope. Paint the inside of both tubes black or line them with black paper to reduce light reflection, which will give you clearer images. Let any paint dry completely before moving on.
  3. Attach the Lenses. Tape the weaker magnifying glass (usually the larger one) to one end of the big tube - this will be your objective lens that faces what you're looking at. Tape the stronger magnifying glass to one end of the smaller tube - this becomes your eyepiece. Make sure both lenses are centered and securely attached. The lenses should be clean and free of fingerprints for the best view.
  4. Assemble Your Telescope. Slide the smaller tube into the larger tube with the lenses facing opposite directions. The eyepiece (on the small tube) should be at the end you'll look through, and the objective lens (on the big tube) should point toward what you want to see. Test that the smaller tube slides smoothly - you'll use this movement to focus on objects at different distances.
  5. Test and Use Your Telescope. Start by looking at distant objects during the day, like trees or buildings. Hold the telescope steady and slowly slide the inner tube in and out until the image becomes clear and sharp. Once you've practiced focusing, try looking at the moon on a clear night - you'll be amazed at the craters you can see! For best results, rest your telescope on a table or other steady surface to minimize shaking.