Step 1: Get your stuff together: pencil or pen, scissors or a box cutter, a cardboard tube or cardboard you can roll into a tube, strong glue or duct tape, a piece of paper with words on it, and two lenses or magnifying glasses of different sizes. You can buy them at any suitable shop, but just make sure they are not the same size, otherwise your telescope won’t work.
Step 2: Take some text and lay it flat on your workspace. Using the biggest lens or magnifying glass, hold it near the paper. Then take the smaller lens or magnifying glass and put it between you and the big one. Play around with them, by moving them closer and further apart from one another, until the words on the page become large and clear.
NB: The words will look upside down. Don’t worry; that’s how telescopes work.
Step 3: Measure how far apart the lenses or magnifying glasses are in order to see clearly. You’ll need another person to help with that. Write that measurement down.
Step 4: Take your cardboard tube and measure 2.5cm from one end and mark it with your pencil.
Step 5: At your mark, cut a slot into the tube for your bigger lens or magnifying glass to fit into.
NB: Don’t cut OFF a chunk of tube. Think of it as a mailbox. You want your lens to slip through the opening and sit inside the tube, not fall onto the ground.
Step 6: Using the measurement you wrote down in Step 3, create the distance from your first slot and go up the length of the tube. This is where you make a mark for your smaller lens or magnifying glass. Cut a slot.
Step 7: Slide your lenses or magnifying glasses into their new homes and secure with glue or duct tape.
Step 8: Trim the tube, if you have excess cardboard, but remember you need at least 1–2.5cm on either end.
Step 9: Using your text, check if your lenses are still the correct length apart to see clearly. Again, the words are supposed to be upside down, you just need them clear. You want the object you are looking at to be in focus.
Step 10: Once your refracting telescope is ready, you can use it to see the moon more clearly. Unfortunately, stars are too far away to see well with your homemade ’scope, but it’s better than no telescope at all!