As we dip our toes into astronomy and start using binoculars and telescopes, a curious child might think… wow… HOW?
Take our binoculars. Piece of glass on one end, piece of glass on the other end, and a tube between them. When we adjust the focus, the tube becomes a little bit shorter or longer. How hard can it be? Everyone gets two lenses, paper, and tape. At first it seems as though lenses are useless: if we bring one to our eyes, we just see a blur, if we move it away from our eyes, we see more blur. But we persevere, and at just about the right distance… (of course, when using small, less break-prone lenses, the results won’t equal a professional telescope…) IT WORKS!
Is the eye looking through the lens somehow cause the image to take shape? Ok, let’s NOT look through the lens, but project an image through the lens. Conclusion: no, the eye is not required. What is required is light.
Next, we need to figure out what happens when light goes through lenses. Luckily, we can do just that.
There are other lens arrangements, and other types of lenses, that we can experiment with.
