“How do old-school telescopes work?”
Telescopes are one of the most amazing machines that humanity has constructed. Not only have they become a symbol for scientific endeavor but a cultural landmark as well. However, have you ever wonder how they worked (specifically the old-school ones)? Well, let’s use our engineering mindset to figure out this scientific device. If we were to uncover the case of these machines, we would find two convex lenses. Now, if we were to trace a ray diagram through the lenses, we would find something very interesting. First, the incoming light from the object would converge onto a real image on the opposite side of the first lens. The light from this image would then be received by the second lens, which shifts the light’s direction in such a way that their paths would converge on the receiving side of the lens, forming a magnified virtual image, therefore creating an enlarged image that the human eye can see. This form of a telescope is called a refracting telescope, and has been used since the days of Galileo!