- 1). Paint the inside and outside of your paper towel tubes black using your paintbrush. If you have a hard time covering the entire inner surface, try pouring the paint into the tubes, allowing it to slide down the insides. Allow your tubes to dry.
- 2). Affix your small convex lens directly inside the end of one tube. Secure the lens in place with your hot glue. If the lens is too small, cut a ring out of the corrugated cardboard to fill in the extra space.
- 3). Secure your large lens to the end of the second tube using your hot glue. Wait for the glue to dry completely.
- 4). Insert your tube containing the small lens into the second tube. Your lenses should be at opposite ends of the tubes, with the overlapping tube segments in the center.
- 5). Look through the tube, positioning your eye directly in front of the small lens. Aim the telescope at an object roughly 20 meters away.
- 6). Focus the amateur telescope by adjusting the distance that the tubes overlap.
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