Distant galaxies and stars are too way out there for us to reach and we are unable to go to them to study them. As such, everything that is known about distant galaxies and stars comes from examining the radiation produced from them. Telescopes are essentially devices that are used to examine the universe. There are a number of different types, some of which are even located in space. So, to answer the question of whether there are telescopes only used on earth? The answer is no.
For thousands of years, individuals have been making and utilizing lenses for amplification. However, it was in the late 16th Century that the first real telescopes were produced in Europe. A combination of two lenses were used in these telescopes to make faraway objects appear both larger and nearer. Galileo Galilei, an Italian scientist and mathematician is credited for having coined the term ‘telescope.’ Galileo’s first telescope was built in 1608 and many improvements to the design were made subsequently.
Telescopes that are reliant on the bending or refraction of light by lenses are simply referred to as refractors or refracting telescopes. All of the earliest telescopes were refractors and a number of the small telescopes amateur astronomers use today are also refractors. These telescopes are ideal for viewing elements within our solar system like the rings around Saturn and the surface of the earth’s moon.
In about 1670, Sir Isaac Newton, another renowned scientist and mathematician created a different type of telescope. To focus light, Sir Isaac used curved mirrors and thus produced the very first reflectors or reflecting telescopes. The mirrors used in this type of telescope are a lot lighter than the hefty glass lenses used in refractors. This is important to note because a refractor has to be heavy and strong to support its thick glass lenses. Additionally, mirrors are easier to create with precision than to create glass lenses.
As such, larger reflectors can be made since there is no need for them to be as heavy to provide support for the same size lens. When telescopes are larger, more light can be collected, making it possible for more distant or dimmer objects to be studied. Today, reflectors account for the biggest optical telescopes in the world.
Thousands of ground-based telescopes are in operation across the world, with astronomers gaining new knowledge by capturing images of new views of the universe on a daily basis. The LBT or Large Binocular Telescope is among the largest telescopes across the globe; it was built in Italy and in 2002, it was transported to Arizona. It is controlled by the University of Arizona and has been utilized in a multitude of astronomical discoveries. This includes the capture of the very first images of a developing planet in 2015.
Telescopes based on the ground have long been the mainstays of astronomical research. In comparison to space-based telescopes, the ground-based ones have a lot to offer. Less money can be used to build bigger telescopes and they are easier to upgrade and maintain. Speaking practically, there is also a much lower risk of them being dented by space junk or the more than 500,000 bits of debris zooming through the cosmos.
However, engineers and scientists are turning to space more and more as the new frontier for sophisticated telescopes. It was in the 1960s when the inclination toward space telescopes started. During that era astronomers begun attaching gigantic balloons to telescopes in order to lift them above the lower atmosphere of the earth to achieve a sharper view. Typically, these ground-based devices are located in elevated, isolated areas with little light pollution. For example, the LBT, is located in the Pinaleño Mountains and stand at 11,000 feet; however, it is not free from atmospheric distortion.
When a ground-based telescope observes the cosmos and captures an image, the light captured initially travelled through the atmosphere. If there is turbulence in the air, the light becomes blurred and result in “atmospheric distortion.” This is why stars appear to twinkle when they are viewed from Earth. This has also contributed to the inability of many ground-based telescopes to capture very sharp images of space objects. For certain research projects, the quality of the image is not vital; however, for researchers who require high-resolution images, many ground-based telescopes would simply not work.
Essentially, telescopes used on earth are limited because the electromagnetic radiation gathered has to pass through earth’s atmosphere. Radiation is blocked and light is distorted by certain elements in the atmosphere. To curtail these issues, several observatories are constructed high on mountains, where less atmosphere is above the telescope.
However, space telescopes eliminate such problems entirely since they orbit in space, outside of the earth’s atmosphere. Space telescopes also have the capacity to carry instruments to monitor objects producing various types of electromagnetic radiation.
In the decades following the giant-balloon strategy which occurred the 1960s, it was obvious that what was actually required were free-flying space telescopes; telescopes that would have the capacity to orbit on their own. As a result, the path to the Great Observatories program was paved.
Perhaps, the Hubble Space Telescope is the most renowned space telescope. The year 1990 was when the Space Shuttle Atlantis put the Hubble into orbit. Once there, scientists realized that the shape of the mirror was flawed. This issue was corrected in 1994 when the Space Shuttle Endeavor went on a servicing mission. Ever since then, the Hubble has supplied enormous volumes of data that have assisted in solving a number the biggest mysteries in astronomy.
Three other major space telescopes have been placed in orbit by NASA, which is the National Aeronautics and Space Administration. They make up what is referred to as the ‘Great Observatories’ by NASA. Each of the three focuses on a different part of the electromagnetic field. Another telescope, the James Webb Space Telescope, is set to be launched by NASA in 2021 to replace the aged Hubble.