Have you ever given a thought over the history of telescopes, has it ever crossed your mind that the telescopes that we sometimes take for granted today, are the reason why we know so much about the Universe. In this article, we will take a quick glimpse at the history of the telescope.
Telescopes are the marvel of human magnificence and they tell us something important about our species. They tell us that we will stop at nothing when we have made up our minds to do something. It has not been long since the first telescope came into the picture, even though the telescopes that were built initially were primitive and not so powerful, but we have made improvements in the telescope design and technology by the rate of leaps and bounds in what can be considered a relatively short amount of time.
The first telescope is widely credited to the Dutch eyeglass maker Hans Lippershey when he submitted his patent for the telescope in 1608. For various reasons, his patent was rejected. However, what he had made was going to change the world in ways more than people at that time could have imagined.
Hans called his design the “Looker”, and he used to see land elements through it. He got the idea for the looker when he observed two kids playing with the lenses, he saw that a distant weather vane appeared to be bigger when seen through the lens. He optimized the placement of the two lenses by arranging them in a tube-like structure and claimed that he got a magnification of 3x.
Hans’s design quickly became famous and the next year in 1609, Galileo heard about the Looker through one of his French associates and quickly set out to make the device on his own. He made considerable improvements and his device offered magnification of up to 20 times. He went down in history to be the first person to point the telescope towards the sky and made groundbreaking observations. With his design, he was able to make out the cratered surface of the Moon, drew the phases of the Moon in detail, saw the moons of Jupiter, saw the rings of Saturn, and even saw the Sunspots.
After the works of Hans Lippershey and Galileo, Johannes Kepler made detailed studies of telescope optics and devised the Keplerian telescope in 1611. His device offered improved magnification, but the image was upside down because of the use of two convex lenses. Apart from making the telescope, Kepler did some groundbreaking work in the field of optics and described the phenomenon of refraction in the eye, the idea of depth perception, he explained real, virtual, upright, and inverted image, and he also explained the concept of magnification. All of this work in the field of optics would earn him the title of ‘Founder of modern optics’.
Dutch Astronomer Christian Huygens, inspired by the work of Galileo and Kepler, sought out to make the world’s most powerful telescope in 1655. Huygens’s biggest contribution was probably the invention of tubeless telescopes. He also made major improvements in the grinding of lenses beginning from 1654. Within a year he was able to put together a 12-foot telescope. He used it to make detailed observations of Saturn and found its bright moon, Titan. Although the name ‘Titan’ was given by John Herschel in 1847.
In 1668, Isaac Newton would become the first person to make a reflecting type telescope. A telescope that uses mirrors instead of lenses. He built on the idea that the problem of chromatic aberration could never be solved in refracting telescopes. Although the idea of a reflecting telescope was not new when Newton designed it, other astronomers before him have pointed out the problem of chromatic aberration and suggested that mirrors should be used instead of a lens to make telescopes, but Newton was the first person to build one. His telescope had many advantages like:
No chromatic aberration.
They were cheaper to build.
Construction and assembly were simpler compared to previous telescopes.
Wide field of view.
The design was shorter as compared to refractors, therefore more portable.
In 1729, Englishman, Chester Moore Hall, solved the problem of chromatic aberration greatly. He introduced a new form of the lens for refracting telescopes. This lens consisted of two glasses, one was called the crown and the other was called the flint which was cemented together. In 1733 he built several small telescopes with the new lenses and these lenses were called the achromatic doublet since they contained two lenses merged as one.
The reflector telescope was the popular choice for anyone who wanted to do Astronomy because they had several advantages over refractors. Earlier reflector telescopes were made from speculum which is a heavy alloy of Copper and tin. They were hard to cast and they quickly get damaged during winters and in rains. In modern-day we can easily make telescope mirrors larger than 9 meters in diameter. However in 1897, the world’s largest refracting telescope was built in Williams Bay, Wisconsin. It was called the Yerkes Observatory. Founded by George Hale and paid for by Charles Yerkes, the Yerkes observatory pushed the limits of the size of refracting telescopes that were possible to build. It houses a spectacular 102 cm diameter doublet lens and is still the largest refracting lens ever built by humans for Astronomy.
In the coming years, Radio telescopes would be born. We would send telescopes in space and many more advanced telescopes will be built to study the X-ray and Gamma-ray spectrum. These photons have so much energy that exposure to them for longer duration can cause the cells in our body to lose their ability to reproduce which can lead to cancer. In 1991, the Compton Gamma Ray Observatory was deployed in space to detect photons with the energy of 20 keV to 30 GeV (Kilo electron volt and Giga electron volt).
The Hubble Space telescope was sent to lower Earth Orbit in 1990, it has done groundbreaking work in the field of Astronomy because of its ability to see without the atmospheric limitations. The Hubble does not have the largest mirror for a reflecting telescope, but it can still give many clear images because being in space gives it the advantage. Here on Earth, we have Keck observatory on Mount Kea in Hawaii. It is the second-largest telescope to be built on Earth and it was built from 1990 to 1996 and uses two telescopes to improve its capabilities to see into the cosmos. The Keck Observatory uses smaller hexagonal mirrors to form a large mirror. Both the mirrors of the twin keck telescope are 10 meters in diameter and each of them is composed of 36 segments of smaller hexagonal mirrors.
In 2018, NASA delayed the launch of the James Webb Space Telescope which is supposed to be the replacement for the aging Hubble Space Telescope. Once deployed it will offer many times higher resolution than the HST. It will be a huge step forward as it will give us important data for Astrophysics and Cosmology. The JWST will supposedly launch in 2021 and will mark the beginning of a new era in the history of Telescopes.
If you are interested in learning about telescopes then check out our online course Hands-On Telescopes. It is a complete guide for anyone who wishes to start out in the world of stargazing and it will get you hooked in the amazing world of Astronomy and Space Science.
Get all the highlights in the night sky of 2020. A great compilation for astronomy enthusiasts to enjoy the upcoming breathtaking celestial shows. Major planet visibility, Conjunctions, Meteor Showers, Moon Phase, Special Events, etc. The night sky is ever-changing and it always has something to observe which should not be missed because you don’t know when it’s going to happen next. But it is also not easy to know all the important things which will happen in our night sky. And that is why we bring for you a new series of videos in which we will be telling you all the major events that will happen throughout the month. All you have to do is note them down and observe them at the right time. We are working hard for bringing this information to you, if you like our content please hit the thumbs up button, consider subscribing to our channel and press the bell icon so that you can get notified whenever we upload any new content.
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