What Are Optical and Radio Telescopes?
It has been centuries since humankind has gazed skywards and pondered the mysteries of the universe. Over time, we have gone from using the unaided eye to the most sophisticated of instruments in order to explore the secrets that space holds. Among the many fantastic tools which allow us to peek into the vastness of our universe are optical and radio telescopes. They enable us to explore areas of the sky which may not be visible to the naked eye and interpret the signals which are sent our way.
What are Optical Telescopes?
An optical telescope is a device which uses an arrangement of lenses, curved mirrors and other optically-oriented components to magnify an image of the objects in space which are far away. It works by collecting and focusing light in order to make distant objects appear nearer. Optical telescopes are often categorized as either reflecting or refracting; reflecting telescopes use mirrors whereas refracting telescopes make use of lenses.
Optical telescopes have been in use since the early 1600s when Galileo Galilei designed the first of its kind which allowed humanity to observe craters that existed on the moon. As time has gone by, optical telescopes have become increasingly sophisticated and have been used to discover planets outside of the Solar System and make detailed observations of those which are within it. Nowadays you can find optical telescopes of various types and sizes; from various backyard designs to some of the largest and most powerful ones, like the Hubble Space Telescope.
Advantages of Optical Telescopes
There are many advantages to using an optical telescope to observe outer space. Some of the most notable ones are:
-
Resolution: Optical telescopes can provide much greater levels of detail in an image compared to other types of instruments like radio telescopes. They are able to pick up on very small changes in brightness which can be used to discern features that are too small for the naked eye to detect.
-
Depth Perception: Optical telescopes can be used to determine the distance between various objects which are located light-years away from one another.
-
Versatility: Optical telescopes can be used to observe a wide range of objects including planets, stars and galaxies. In addition, they can also be used to measure the chemical composition of distant objects by detecting their light spectrum.
Disadvantages of Optical Telescopes
Like any type of instrument, optical telescopes also have their drawbacks. Two of the most significant are:
-
Atmospheric Distortion: Optical telescopes rely on the atmosphere to transmit light to the device in order to generate your image. This means that when looking at very distant objects, the image could become distorted depending on the condition of the atmosphere.
-
Expensive: Unlike radio telescopes, optical telescopes can be quite costly to own and maintain. This is mainly because they require specialized hardware and skilled personnel in order to take full advantage of its capabilities.
What are Radio Telescopes?
Radio telescopes are instruments which are designed to detect radio waves from celestial sources. Unlike optical telescopes, these devices can pick up on various types of radiation which are not normally visible to the human eye, including radio waves.
The earliest radio telescopes were developed in the 1930s and 40s, with the purpose of measuring the radio energy from extraterrestrial sources such as stars and galaxies. As technology has evolved, so too have radio telescopes, and today they are capable of taking sharp images at different frequencies in order to allow humanity to observe objects that were previously undetectable with optical telescopes.
Advantages of Radio Telescopes
Radio telescopes have several advantages to those of the optical variety.
-
Free of Atmospheric Distortion: Since it works with radio waves which are immune to atmospheric conditions, images generated through a radio telescope are always guaranteed to provide clear and detailed images which are free of distortion. Additionally, radio telescopes also have the ability to “see” through clouds, thus providing imagery of regions which optical telescopes would not be able to penetrate.
-
Expansive Field of View: Thanks to their ability to detect radio waves, radio telescopes can observe a much larger area of space compared to optical telescopes; up to an entire hemisphere in some cases. This makes them ideal for spotting large-scale objects such as galaxies and nebulas.
-
Time Efficient: Radio telescopes take considerably less time to acquire a signal than optical telescopes. This is mainly due to the fact that radio signals reach the earth in milliseconds as opposed to the minutes or hours which are required for light energy to travel from its source.
Disadvantages of Radio Telescopes
Radio telescopes are not without their own set of downsides. These include:
-
Limited Resolution: Compared to optical telescopes, those that use radio waves offer less detailed images. This is mainly due to the fact that radio waves are significantly less focused than light waves. Thus, small objects, such as stars and planets, can be difficult to observe with radio telescopes.
-
Interference: Radio waves are, at times, interfered with by external signals such as those created by power lines and other devices. This can blur the signal which is sent to the telescope and make it difficult to produce a clear image.
Optical and radio telescopes are remarkable tools which allow us to explore the farthest reaches of outer space. By making use of lenses, mirrors and radio waves, these tools give us the ability to detect the tiniest of details which may otherwise be invisible to the unaided eye. Whereas optical telescopes offer higher resolutions and depth perception, radio telescopes have the advantage of being immune to interference from the atmosphere and provide expansive fields of view. All in all, these tools offer us the ability to embark on an exciting journey and discovery of the mysteries that the universe holds.
