Thanks to a telescope, Galileo Galilei was able to observe the Moon, the stars and Jupiter in 1610. Now, our planet has multiple observatories with gigantic ground-based telescopes observing the solar system and far beyond. In addition, we have also sent them into space, with the idea of investigating more about the universe.
Before talking about the types of ground-based telescopes; Let’s talk about what they are and what they are for. Let’s start with optical telescopes, which are the best known (although not the only ones). An optical terrestrial telescope is one that is located on Earth and that use lenses and light to magnify images. For example, the classic telescopes for children (or not so young) to observe the stars from the backyard are of this type. And many observatories have huge optical telescopes to observe the universe.
As we said, terrestrial telescopes, be they optical or otherwise, what they do is help us to better observe the bodies that appear in the sky; as the human eye is not enough to distinguish them. This is the main objective of the observatories, hence its name. From looking at the planets of the solar system like Venus or Jupiter, to the most distant stars. We have even managed to take a picture of a black hole with observations that can be made from Earth. However, they are not the only ones; because space telescopes help us too. But we will talk about these a little later.
Types of ground-based telescopes
Photo by Thanh Nguyen on Unsplash
Telescopes can be of various types. The optician is the best known, but they can also be radio telescopes or infrared telescopes.
The radio telescopes they are actually antennas that pick up radio waves. It is different because more than to see it serves to listen. An example is the Very Large Array in New Mexico, SOUL in Chile or, until recently, that of Arecibo. The latter, in addition, is the one that appears in the film Contact.
Another way to look at the sky is through infrared. Thanks to these telescopes you can look through the dust in space, which usually blocks everything; but in the infrared it becomes transparent. In this way, we have access to regions of the universe that we could not have dreamed of before. There are several of these telescopes: the Very Large Telescope the European Southern Observatory (ESO); the Mauna Kea Observatory in Hawaii and the Paranal Observatory in Chile.
In the case of infrared telescopes, it can be said that they are more of a mode than a different telescope. If you look at the examples, some optical and infrared match. As is the case with the Mauna Kea Observatory, the Very Large Telescope and many others that we have not talked about. In short, by means of added instruments it is possible to make an optical telescope observe space through infrared.
Spotting scopes in Spain
Let’s continue with the ground-based telescopes. In Spain there are three observatories: two in the Canary Islands (observatories of the Teide Y Boys roque) and another in Calar Alto (Andalusia).
In Calar Alto they have «three telescopes with 1.23m, 2.2m and 3.5m openings»In the Sierra de Los Filabres, north of Almería. A fourth telescope of 1.5m It is located in the mountains, although it is operated by the Madrid Observatory, as explained on their website.
At the Calar Alto Observatory they have several instruments that help to better understand the universe. One of them is CARMEN IS, which is a ‘spectrograph’ that ‘was designed to search for terrestrial planets in the habitable zone; or region around a star where conditions allow the existence of liquid water “, indicate from the Institute of Astrophysics of Andalusia (IAA).
At the Teide Observatory they have specialized in observing the Sun, although this is not the only thing they do. But due to “its geographical location” and “together with the transparency and excellent astronomical quality of its sky”, this observatory is preferably reserved to observe our star, as explained by the Instituto de Astrofísica de Canarias (IAC, for its acronym) .
«The best European solar telescopes, such as the GREGOR, 1.5 m in diameter, and perhaps the future European Solar Telescope (EST), which with a diameter of 4 m will be the largest in Europe for these studies ”.
The sky of the Canary Islands seems to be an extraordinary place for observation as it houses two observatories. «Thanks to the sky of La Palma, this observatory meets the best conditions for astronomical research«, They indicate from the IAC.
The Roque de los Muchachos Observatory houses the «largest optical and infrared telescope in the world«
Canary Islands Astrophysics Institute (IAC)
These conditions are so fundamental to astronomy that the Roque de los Muchachos Observatory “is attracting some of the giant telescopes of the future as well as the new generation of Cherenkov telescopes for the study of the universe in very high energy gamma rays ».
But let’s talk about what is currently in this observatory. And it is that at the moment the IAC has in La Palma the “largest optical and infrared telescope in the world” and “about twenty other telescopes and instruments astronomical for different types of study ».
Photo by NASA on Unsplash
These are some of the current ground-based telescopes. But let’s talk about space telescopes and what advantage they have in front of the earthlings.
One of the great difficulties when looking at space from Earth is the atmosphere. This can interfere with observations in two ways. The first is by distorting the images. And the other has to do with ultraviolet telescopes. And it is that ultraviolet energy barely passes through the atmosphere.
This is one of the reasons why some are sent into space, such as the hubble space telescope, which is on the verge of retirement. Or the James Webb space telescope that, if everything goes according to plan by NASA, the European Space Agency (ESA) and the Canadian Space Agency (CSA); will go into space next October.
This is only a very basic approach to the types of telescopes, terrestrial or space, that there are. We have not discussed the types of optical telescopes or all the work that can be done with them. From seeing supernovae to finding new exoplanets. What is important is to be clear that the telescopes are one of the basic tools of astronomy. Because looking at the sky with our eyes alone is not enough.