Who Invented The Telescope?

Understanding and exploring the cosmos has fascinated us for aeons. As early as the ancient Greeks, we’ve had ideas about the universe. Mathematicians and astronomers such as Claudius Ptolemaeus and Hipparchus of Nicea were able to create images of the solar system using the principles of geometry and the naked eye. These early models placed Earth at the centre with the planets orbiting it, this stemmed from a belief that Earth was divine and therefore, held a special and geocentric significance within the cosmic order.

The invention of the telescope in the 17th century revolutionised our ability to study the universe. In the Netherlands, in 1608, three different telescopes were created independently of each other by spectacle makers: Hans Lippershey, Zacharias Janssen and Jacob Metius. When Lippershey put forward his kijker (or ‘looker’) for a 30-year patent, it prompted claims to the invention from Janssen and Metius. As a result, no patent was awarded because the invention was so easy to replicate! Word of the kijker and the importance it might hold for astronomy quickly spread across the world, leading to Galileo building his own.

More History On The Telescope

Using the telescope, Galileo was able to make several amazing discoveries. Some of these include the four moons of Jupiter, the fact that the Earth is not spherical but an ellipsoid and that the Sun was the centre of the solar system, not the Earth as previously believed. All in days work, right?

The use of telescopes was not limited to scientists, they were popular in society to observe the moon. According to Royal Museums Greenwich, Sir Wiliam Lower wrote, "in the full she appears like a tarte that my cooke made last weeke.”

In the 20th century, scientists began manufacturing telescopes that gathered other parts of the electromagnetic spectrum rather than light, such as x-rays, ultraviolet, infrared and gamma rays. And in 1990, NASA and the European Space Agency launched the Hubble Space Telescope into orbit. Hubble is the size of a large school bus and can travel 5 miles per second. Because it floats above our atmosphere it can capture more impressive images of space events. Some of its achievements include pictures of the birth and death of stars, comet pieces crashing into Jupiter and universes billions of light years away.

In 2021, the new and more advanced James Webb Space Telescope was launched. It can observe objects too old, too distant or too faint for Hubble. Already it has provided key insights into how planets are made.

How Does a Telescope Work?

Most telescopes use curved mirrors, called optics, that collect and focus light from the night sky. In the early days, manufacturers used curved glass for this purpose. However, the evolution of technology has led to a preference for mirrors, owing to their more favourable characteristics, such as low weight and a smoother surface. To capture images from areas of space light years away, the optics in a telescope need to be very large. Additionally, the surface must be completely free of imperfections such as scratches or smudges to avoid blurry or warped images.

There are two main types of telescopes: refracting and reflecting.

The Reflecting Telescope

The reflecting telescope, pioneered by Sir Isaac Newton, uses mirrors to gather and focus light. When light enters the telescope, it is directed to a focus point forming an image. Some reflecting telescopes will have a secondary mirror to redirect the light to a more convenient position and sharpen the image.

The Refracting Telescope

The refracting telescope uses glass lenses instead of mirrors to gather and focus light; this is called an objective lens. The lens collects the light and directs it at the focal point where it can be observed through an eyepiece. Though refracting telescopes can still be found commercially, they are not often used by professional astronomers. This is due to common chromatic aberration, where the glass lens cannot focus all the light colours at the same position resulting in colour fringing, which forms a blurry purple border around the image. Other consequences of chromatic aberration include blurring, reduced contrast, and colour distortion.

From Ancient Greek mathematicians to 16th-century spectacle makers to modern NASA scientists to you, the desire to learn and discover unites us all. At Army Cadets, we encourage this spirit of discovery and exploration through expeditions. We recognise the importance of the sky above us in these adventures. For example, Army Cadets teamed up with key navigation experts to give you the best advice on how to find the North Star, a lifesaver if you are lost without Google Maps! To learn more, find your nearest detachment and get involved.

Image Credit

Galaxy: Guillermo Ferla, used with permission.

Observatory: Conner Baker, used with permission.