acap - Why was the use of the telescope by Galileo, 400...

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Why was the use of the telescope by Galileo, 400 years ago, such a significant event in the history of astronomy? (120 words, 2 marks) Galileo first pointed his telescope at the moon and he learned that moon’s surface was not smooth. He observed that moon was covered by craters and mountains. This observation helped prove that the heavenly bodies were not perfect as taught by Catholic Church. Through his telescope, Galileo found many evidences that support the Copernican Sun centered universe instead of Earth centered universe. He discovered four satellites orbiting Jupiter which today is known as the Galilean satellites. These satellites are the four largest Jupiter’s moons. This reinforced his view that it is possible for bodies to orbit something rather than just the Earth. Next, Galileo also observed the phases of Venus, which are a lot like the Moon’s phases. Galileo observed that all of its phases, and the only logical explanation to this event is Venus was orbiting the Sun, not the Earth. It was the very first conclusive and observational proof that the universe is sun-centered. Galileo has ultimately proved that earth-centered universe was totally incorrect. Glass photographic plates were once the standard detector for astronomical imaging. Describe the type of detector that has replaced photographic plates and outline what its advantages are. (100 words, 2 marks) In the 1980s, electronic detectors like Charge Coupled Devices (CCDs) had replaced photographic plates. CCDs have many advantages compared to photographic plates. CCDs have higher sensitivity compared to photographic plates. Its sensitivity or quantum efficiency is simply the fraction of photos incident on the chip which are detected. Next, CCDs are sensitive to wide range of light levels and has a higher dynamic range (the ratio of the brightest accurately detectable signal to the faintest one). Furthermore, this dynamic range gives a linear response that is the size of the signal is proportional to the number of photons detected, making a straightforward calibration. CCDs also allows digital images to be recorded and stored in a computer. What is the advantage of putting telescopes in space, as compared with the use of ground-based
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acap - Why was the use of the telescope by Galileo, 400...

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