types of telescopes

The father of modern astronomy in 1609, the Italian physicist Galileo Galilei, who was responsible for proving that the Earth revolves around the sun, did something that forever changed the history of science and the way we view the universe. He invented the telescope. Since then, different types of telescopes as technology advances. We find telescopes that only scientists can use and telescopes for ordinary people.

For this reason, we are going to dedicate this article to tell you about the different types of telescopes that exist, their characteristics and what function each one of them has.

What are telescopes

A telescope is an optical instrument that allows you to observe distant objects and celestial bodies in greater detail than can be seen with the naked eye. Namely, it is a tool capable of trapping electromagnetic radiation such as light.

The ability of telescopes to process electromagnetic waves, including those of the visible spectrum, leads us to emphasize that although the general idea that telescopes magnify the size of objects through a series of lenses, not true.

In other words, instead of magnifying the image with a magnifying glass, the telescope collects the light (or other form of electromagnetic radiation) reflected from the objects in the universe that we want to observe and, after processing this light information, reconstructs it into a image. They do not enlarge the image.

types of telescopes

There are about 80 different types of telescopes, but the differences between many of them are very subtle and only relevant from a very technical point of view. Therefore, we have compiled all these types and divided them into basic families based on the type of electromagnetic radiation they can handle and their basic design.

optical telescope

When we think of telescopes, we basically think of optical telescopes. They are capable of processing the part of electromagnetic radiation that corresponds to the visible spectrum, which it has wavelengths between 780 nm (red) and 380 nm (violet).

In other words, they are telescopes that capture the light from the objects we want to observe. These implements are capable of increasing the apparent size and brightness of objects. Depending on how they capture and process light, optical telescopes can be divided into three main types: refractors, reflectors, or catadioptric mirrors.

refracting telescopes

A refracting telescope is an optical telescope that uses lenses to form images. Also known as diopters, they are the ones used before the introduction of more advanced technology in the early XNUMXth century, and are still used by amateur astronomers.

It is the best known type of telescope. It consists of a set of lenses that capture light and focus it on what is called the focal point, where the eyepiece is located. Light rays refract (change direction and speed) as they pass through this converging lens system, causing parallel rays from distant objects to converge to a point in the focal plane. It allows you to see large, bright and distant objects, but is very limited on a technical level.

Reflecting telescope

A reflecting telescope is an optical telescope that uses mirrors instead of lenses to form an image. It was originally designed by Isaac Newton in the XNUMXth century. Also called reflectors, they are especially common in amateur astronomy, although professional observatories use a variant called Cassegrain that is based on the same principle but has a more complex design.

However, it is important that they are made of two mirrors. One is at the end of the tube and is the one that reflects the light, sending it to a mirror called the secondary mirror, which in turn redirects the light to the eyepiece. Resolves some issues with refractors, as not wearing lenses resolves some chromatic aberrations (not as much brightness distortion) and allows you to see objects further away, even though they are of lower optical quality than refractors. As such, they are useful for observing more distant faint objects, such as galaxies or deep nebulae.

catadioptric telescope

A catadioptric telescope is an optical telescope that uses lenses and mirrors to form an image. There are many types of this type of telescope, but the most famous is the one we mentioned earlier: the Cassegrain telescope. They are designed to solve the problems posed by refractors and reflectors.

They have good optical quality (not as high as refractors), but they won't let you see distant, dim objects like reflectors. This type of telescope has three mirrors. There is a primary mirror located in the rear area, which is concave in shape to focus all the light it collects on a point called the spotlight. Then a second convex mirror in front reflects the image back to the primary mirror, which reflects the image to a third mirror already sending the light to the target.

radio telescope

We completely changed the terrain and continue to look at the telescopes, which, while they are telescopes, certainly do not match the telescope images that we have. Radio telescopes consist of an antenna that captures electromagnetic radiation corresponding to radio waves, that have wavelengths between 100 microns and 100 kilometers. Instead of capturing light, it captures the radio frequencies emitted by celestial objects.

infrared telescope

Infrared telescopes consist of an instrument capable of capturing electromagnetic radiation corresponding to infrared rays, whose waves have wavelengths between 15.000 nm and 760-780 nm, thus limiting the red portion of the visible spectrum that does not capture light but infrared radiation. These not only completely eliminate interference from Earth's atmosphere, but also give us very interesting information about the "heart" of the galaxy.

x-ray telescope

An X-ray telescope is an instrument that can view celestial objects that emit electromagnetic radiation in the X-ray spectrum, with wavelengths between 0,01 nm and 10 nm. They allow us to detect objects that do not emit light, but rather what we usually call radiation, such as black holes. Since Earth's atmosphere does not allow these X-rays from space to penetrate, these telescopes must be mounted on satellites.

ultraviolet telescope

An ultraviolet telescope, an instrument that allows us to see celestial objects, emits electromagnetic radiation in the ultraviolet spectrum, with wavelengths between 10 and 320 nanometers, so it is a radiation close to X-rays. In other words, these telescopes provide very valuable information about the evolution of galaxies and white dwarfs.

Cherenkov telescope

The Cherenkov telescope is an instrument that detects gamma rays from energetic objects such as supernovae or very active galactic nuclei. Gamma radiation has a wavelength of less than 1 picometer. There are currently four such telescopes in the world and they provide very important information about the astronomical sources of these gamma rays.

I hope that with this information you can learn more about the types of telescopes that exist and their characteristics.