In , Galileo was appointed professor of mathematics at the University of Padua and made frequent trips to the Arsenal — the inner harbor where Venetian ships were fitted out. The Arsenal had been a place of practical invention and innovation for centuries, and Galileo used the opportunity to study mechanical devices in detail.
In , he was consulted on the placement of oars in galleys and submitted a report in which he treated the oar as a lever and correctly made the water the fulcrum. A year later the Venetian Senate awarded him a patent for a device for raising water that relied on a single horse for operation.
This became the basis of modern pumps. During the 16th century, Aristotelian physics was still the predominant way of explaining the behavior of bodies near the Earth.
For example, it was believed that heavy bodies sought their natural place or rest — i. As a result, no means existed to explain the behavior of pendulums, where a heavy body suspended from a rope would swing back and forth and not seek rest in the middle. Already, Galileo had conducted experiments that demonstrated that heavier bodies did not fall faster than lighter ones — another belief consistent with Aristotelian theory.
In addition, he also demonstrated that objects thrown into the air travel in parabolic arcs. Based on this and his fascination with the back and forth motion of a suspended weight, he began to research pendulums in In , he explained his observations in a letter to a friend, in which he described the principle of isochronism. TIP : This lecture series on the technology throughout history by Derek de Solla Price from Yale talks about how ancient man went from hunter and gatherer to astrologer and astronomer.
Lecture 7 , Lecture 8 , Lecture 9 , Lecture 10 touch on the history of the telescope. The telescope is actually credited to Hans Lippershey in Fact Myth. This happens in refractors because different colours of light are bent very slightly differently as they pass through the lens, which results in a blurred image.
Chromatic aberration can be overcome by using achromatic lenses, which consist of two or more lenses made out of different types of glass joined together to form a compound lens, but this is expensive and technically difficult when constructing larger lenses. The main advantage of reflectors is that it is much easier to produce a large mirror than a large lens. A large lens many metres in diameters would be very thick, very heavy and difficult to manufacture to the quality needed in a telescope.
It would also tend to sag, becoming deformed under its own weight, producing a blurred image. For these reasons the largest refractor used in professional astronomy is the one at Yerkes Observatory. It has an objective lens which is 1 metre in diameter.
All telescopes larger than this are reflectors. It is based at Williams Bay, Wisconsin and was operated by the University of Chicago until its closure in To calculate the magnification of a Galilean telescope, we divide the focal length of the objective by the focal length of the eyepiece. So, if the focal length of the objective is cm and the focal length of the eyepiece is 10 cm, the magnification of the telescope would be To view it, please click on the link below.
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Notify me of new posts via email. This site uses Akismet to reduce spam. So, who invented this incredible cosmic time machine? It seems like a simple idea: put lenses together to gather up light or magnify dim and distant objects. It turns out telescopes date back to the late 16th or early 17th century, and the idea floated around for a while before telescopes came into widespread use. A lot of people think Galileo came up with the telescope.
It's well known that he built his own, and paintings often show him looking through the sky at his own instrument. He also wrote extensively about astronomy and observations.
But, it turns out he was not the telescope's inventor. He was more of an "early adopter". Yet, that very usage of it prompted people to assume he invented it. It's far more likely he heard of it and that's what started him building his own. For one thing, there's a lot of evidence that spyglasses were in use by sailors, which had to come from somewhere else. By , he was ready for the next step: pointing one at the sky.
That's the year he began using telescopes to observe the heavens, becoming the first astronomer to do so. His first construction magnified the view by a power of three. He quickly improved the design and ultimately achieved a power magnification. With this new tool, he found mountains and craters on the moon, discovered that the Milky Way was composed of stars, and discovered the four largest moons of Jupiter. What Galileo found made him a household name.
But, it also got him in a lot of hot water with the church. For one thing, he found the moons of Jupiter. From that discovery, he deduced the planets might move around the Sun the same way those moons did around the giant planet.
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