How to Make a Telescope from a Paper Towel Roll

A telescope can open up an entirely new and fascinating world to those who peak through its magnified lens. Do you want to feel like you have the moon in the palm of your hand? The moon, stars and various wildlife can appear to be in reach with the help of a telescope.
With a few magnifying glasses, a paper towel tube, a ruler and a scientific eye, the stars are the limit.

Difficulty: Moderately Challenging

Instructions

Things You'll Need:

• Two magnifying glasses
• Cardboard paper towel tube
• Heavy duty tape
• Ruler
• Scissors
• A friend

How to Make a Telescope from a Paper Towel Roll

1. Gather two magnifying glasses. One magnifying glass should be around 3 cm in diameter, while the other should be about 3.5 cm. The measurements can be different so long as one magnifying glass is larger than the other and they are not significantly larger than the paper towel tube. The larger magnifying glass should be weak in strength and the smaller one should be more powerful.

2. Hold the smaller, more powerful magnifying glass up to your eye. This is the eye piece. Bring the larger magnifying glass up to the smaller and look through it. Things will appear blurry and upside down.

3. Shift the larger magnifying glass backward and forward until everything comes into focus.

4. The distance between the two magnifying glasses needs to be measured. Ask a friend to measure the distance with a ruler and jot down the findings.

5. Measure 2.5 to 3 cm from the front of the tube and mark it with a pen. Cut a slot into the tube where you marked. Make sure not to cut the tube in half. Only cut about two thirds through the tube. The larger, weaker magnifying glass will fit into this slot.

6. Another slot must be cut for the smaller magnifying glass. Go back to the measurement you jotted down earlier. The distance between the first slot and the second slot should be exactly this same measurement. Use a ruler to measure this distance and cut the second slot.

7. Fit the two magnifying glasses into their appropriate slots. The larger one should be placed in the first slot and the smaller one in the second slot. Secure the magnifying glasses with heavy duty tape.

8. Trim the end of the cardboard tube (the portion behind the second, smaller magnifying glass), allowing only 2 cm of tubing to protrude from behind the second magnifying glass.

9. Look through the cardboard tube. Everything should appear in focus and magnified. Your cardboard tube is no longer a mere cardboard tube, but a telescope.

Tips & Warnings

• Strapping tape or duct tape will work best to secure the magnifying glasses to the tube. If your telescope is out of focus, adjust where the magnifying glasses are placed.