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How Telescopes Work
A look into the night sky is a journey into the past. Why? Because light takes a while to travel long distances. That's where telescopes come in.
Take the star Bellatrix in the constellation Orion, for instance. It is so far away from Earth that the light we see from it is 300 years old! A telescope that is able to gather and focus visible light can see farther and deeper into the past than a naked eye. The key is that it is bigger than an eye and can collect more light. When it brings that light into focus, it provides a magnified image. Two types of optical telescopes are refractors and reflectors.
