History of Telescopes

Whenever you listen to the word “Telescope,” many thoughts about the stars and galaxies come to mind. But have you ever wondered how and who invented the first telescope, or what is the history of optical telescopes? Today, we will be diving into the rich history of telescopes! 

Most people think that Galileo was the one who invented the first telescope. However, Galileo indeed contributed to the telescope’s evolution, but he was not the one who invented the telescope.

The first telescope concept comes from a patent filed by Hans Lippershey, a Middleburg spectacle-maker, with the States-General of the Netherlands on October 2, 1608.

The original Dutch telescopes were constructed in such a way that they did not invert the image. These telescopes were composed of both concave and convex lens. The magnification of the first original telescope was only 3x – which is nothing as compared to the modern power telescopes.

Galileo and the History of Optical Telescopes

Now you might be thinking about what was the role of Galileo in the evolution of optical telescopes? Well, Galileo was the one who revolutionized astronomy by applying the telescope to the study of extraterrestrial bodies (stars and galaxies) in the early 17th century.

This work of Galileo paved the way for many new powerful telescopes. Not only telescopes but his work also paved the way for the invention of various kinds of auxiliary instruments. These include spectrograph, the camera, and charge-coupled device, etc.).

Such kinds of great inventions lead the scientists to discover many new stars and galaxies, including the Milky Way Galaxy.

No doubt, the telescope is the most important instrument in this modern era. Not only for the sake of astronomy, but it has been used by a lot of astrologists as well. In fact, it won’t be wrong to say that the base of astrology stands on the telescope.

Refracting Telescopes

Refracting telescopes or commonly called refractors, are the types of telescopes used to examine the Moon and other planets of the solar system. These other planets include Jupiter, Mars, and some other binary stars.

Johannes Kepler was the first one who explained the theory and practical advantages of using two convex lenses. Kelper just explained the theory and some practical advantages, but Christoph Scheiner constructed the actual first telescope of this type.

The refracting telescopes work on the principle of refraction. This principle is the bending of light waves when they pass from one medium to the other (e.g., glass to air or air to glass). The lenses in the refracting telescopes can be convex, concave, or plane-parallel.

The first lens in the refracting telescope is called an “objective lens” through which the light from the celestial object passes. The second lens is referred to as the “eyepiece,” which is present behind the focal plane, and it enables the observer to view the enlarged image of the object.

So, the simplest form of a refracting telescope consists of an objective lens and an eyepiece to see the object’s magnified image.

Reflecting Telescopes

In the 11th century, Galileo and others observed that the curved mirrors have the same properties as the lenses. They then discussed the idea of building a telescope based on mirrors for making the image of any object.

In 1616, Niccolò Zucchi wrote in his book Optica Philosophia that he tried to replace the lens with the bronze concave mirror, but he was not satisfied with the image because of the poor quality of the mirror.

However, in 1636 Marin Mersenne proposed a telescope consisting of a paraboloidal primary and secondary image that solved the image’s problem.

The name of the reflecting telescope explains its working principle. In a reflecting telescope, the primary mirror reflects the light back to the mirrors instead of refracting the light. The primary mirror is usually of concave parabolic or spherical shape. It inverts the image at the focal point by reflecting the light instead of refracting.

Catadioptric Telescope

A catadioptric telescope is one that incorporates both a refractive lens and a reflecting mirror. The term catadioptric came from two separate words, “catoptric” referring to an optical system that uses curved mirrors and “dioptric,” which refers to lenses’ use.

The following are the most common types of catadioptric telescope designs that astronomers use:

  • Schmidt-Astrograph
  • Schmidt-Cassegrain
  • Schmidt-Newtonian
  • Maksutov-Cassegrain

The catadioptric telescopes are far more beneficial from other telescopes of the same aperture. Like a catadioptric telescope, it is easy to transport and is lighter than the other telescopes of the same aperture.

But if you try to increase them in aperture, they will become heavier than other telescopes. Similarly, when compared to the refracting telescopes, the catadioptric telescope require more frequent optical alignment.

The Bottom Line

The most precious and valuable asset of the astronomers and most astrologists is the telescope. It is a great source for collecting and analyzing the radiation coming from the extraterrestrial object in outer space.

It was because of the evolution in the history of optical telescopes that paved the way for the renowned scientist. In history, towards many valuable discoveries like The MilkyWay Galaxy, the solar system, the comets, and other objects that lie far from us.

The most common types of telescopes are Reflecting Refracting and Catadioptric telescopes. However, these three main types of telescopes are further divided into subtypes based on performance and resolution power.