The telescope is used to... Optical telescopes
How to choose a good optical instrument?
As soon as a person establishes visual contact with space, he looks for an opportunity to look at everything that he sees much closer, to consider as many details as possible. This is what a telescope is designed for, how to choose it correctly?
Nowadays, so many different designs and models have been created that the buyer for a long time stands at a loss - not knowing where to start buying. To begin with, of course, you should decide what you want to see in it and under what conditions you will observe it all. It is imperative to evaluate the living conditions in order to allocate a place for it, and material capabilities, that is, the funds that you can afford to pay for it. However, for the same amount you can buy two different tools.
Types of telescopes
In order to see the galaxy and nebulae, the largest aperture is needed. The usual dimensions of refractor rulers, for some reason, end at around 150 mm. Newtonian telescopes are most suitable for these purposes.
Photographs of planets are most often used using catadioptric telescopes, but they will be unsuitable for photographing a weakly extended object due to the small aperture.
Refractors are very suitable for observing star fields and double stars. You can also use them to view the moon and planets.
Conclusion
The mistake many buyers make is wanting to buy one telescope once and for all. You need to understand that each tool is intended for different objects, fulfills its role and will reveal to you different secrets of our universe. Of course, the enjoyment of your excursion through space will largely depend on you, and not on the telescope. Using even inexpensive tools, you can make your research interesting and unforgettable.
Video guide that describes in detail how to choose a telescope
In this section we tried to put together the fragmentary information that can be found on the Internet. There is a lot of information, but it is not systematized and scattered. We, guided by many years of experience, have systematized our knowledge in order to simplify the choice for novice astronomy lovers.
Main characteristics of telescopes:
Usually the name of the telescope indicates its focal length, lens diameter and mount type.
For example, Sky-Watcher BK 707AZ2, where the lens diameter is 70 mm, the focal length is 700 mm, the mount is azimuth, second generation.
However, the focal length is often not indicated on the telescope labeling.
For example Celestron AstroMaster 130 EQ.
A telescope is more versatile optical instrument than a spotting scope. A larger range of magnifications is available to him. The maximum available magnification is determined by the focal length (the longer the focal length, the greater the magnification).
To display a clear and detailed image at high magnification, the telescope must have a large diameter lens (aperture). More the better. A large lens increases the telescope's aperture and allows you to view distant objects of low luminosity. But as the diameter of the lens increases, the dimensions of the telescope also increase, so it is important to understand under what conditions and for observing what objects you want to use it.
How to calculate the magnification of a telescope?
Changing the magnification in a telescope is achieved by using eyepieces with different focal lengths. To calculate the magnification, you need to divide the focal length of the telescope by the focal length of the eyepiece (for example, the Sky-Watcher BK 707AZ2 telescope with a 10 mm eyepiece will give a magnification of 70x).
The multiplicity cannot be increased indefinitely. As soon as the magnification exceeds the resolving power of the telescope (lens diameter x1.4), the image becomes dark and blurry. For example, a Celestron Powerseeker 60 AZ telescope with a focal length of 700 mm does not make sense to use with a 4 mm eyepiece, because in this case it will give a magnification of 175x, which is significantly greater than 1.4 times the diameter of the telescope - 84).
Common mistakes when choosing a telescope
- The higher the multiplicity, the better
This is far from true and depends on how and under what conditions the telescope will be used, as well as on its aperture (lens diameter).
If you are a beginner astronomer, you should not chase high magnification. Observing remote objects requires high degree training, knowledge and skills in astronomy. The Moon and planets of the solar system can be observed at magnifications from 20 to 100x. - Buying a reflector or large refractor for observations from a balcony or from a city apartment window
Reflectors (mirror telescopes) are very sensitive to atmospheric fluctuations and to extraneous light sources, so it is extremely impractical to use them in urban conditions. Large aperture refractors (lens telescopes) always have a very long tube (for example, with an aperture of 90 mm, the length of the tube will exceed 1 meter), so their use in city apartments is not possible. - Buying a telescope with an equatorial mount as your first
The equatorial mount is quite difficult to master and requires some training and qualifications. If you are a beginner astronomer, we would recommend purchasing a telescope on an alt-azimuth mount or a Dobsonian mount. - Buying cheap eyepieces for serious telescopes and vice versa
The quality of the resulting image is determined by the quality of all optical elements. Installing a cheap eyepiece made from budget optical glass will negatively affect image quality. Conversely, installing a professional eyepiece on an inexpensive device will not lead to the desired result.
Frequently Asked Questions
- I want a telescope. Which one should I buy?
A telescope is not something you can buy without any purpose. A lot depends on what you plan to do with it. Telescope capabilities: show both terrestrial objects and the Moon, as well as galaxies hundreds of light years away (only the light from them takes years to reach the Earth). The optical design of the telescope also depends on this. Therefore, you must first decide reasonable price and the object of observation. - I want to buy a telescope for my child. Which one should I buy?
Many manufacturers have introduced children's telescopes into their range especially for children. This is not a toy, but a full-fledged telescope, usually a long-focus achromat refractor on an azimuthal mount: it is easy to install and configure, it will show the Moon and planets well. Such telescopes are not very powerful, but they are inexpensive, and there is always time to buy a more serious telescope for a child. If, of course, the child is interested in astronomy. - I want to look at the moon.
You will need a telescope “for near space.” In terms of optical design, long-focus refractors, as well as long-focus reflectors and mirror-lens telescopes, are best suited. Choose a telescope of these types to suit your taste, based on price and other parameters you need. By the way, through such telescopes it will be possible to look not only at the Moon, but also at the planets solar system. - I want to look at distant space: nebulae, stars.
Any refractors, short-focus reflectors and mirror-lens telescopes are suitable for these purposes. Choose according to your taste. And some types of telescopes are equally well suited for both near space and far space: these are long-focus refractors and mirror-lens telescopes. - I want a telescope that can do everything.
We recommend reflex lens telescopes. They are good for ground-based observations, for the Solar System, and for deep space. Many of these telescopes have simpler mounts and computer guidance, and are a great option for beginners. But such telescopes have a higher price than lens or mirror models. If price is a factor, you might want to look at a long-focus refractor. For beginners, it is better to choose an alt-azimuth mount: it is easier to use. - What is a refractor and reflector? Which one is better?
Telescopes of various optical designs will help you visually get closer to the stars; the results are similar, but the mechanisms of the device are different and, accordingly, the application features are different.
A refractor is a telescope that uses optical glass lenses. Refractors are cheaper, they have a closed tube (no dust or moisture will get into it). But the tube of such a telescope is longer: these are the structural features.
The reflector uses a mirror. Such telescopes are more expensive, but they have smaller dimensions (shorter tube). However, the telescope mirror may fade over time and the telescope may become blind.
Any telescope has its pros and cons, but for any task and budget you can find the ideal telescope model. Although, if we talk about the choice in general, mirror-lens telescopes are more versatile. - What is important when buying a telescope?
Focal length and lens diameter (aperture).
The larger the telescope tube, the larger the lens diameter will be. The larger the lens diameter, the more light the telescope will collect. The more light the telescope collects, the better dim objects will be visible and the more details will be visible. This parameter is measured in millimeters or inches.
Focal length is a parameter that affects the magnification of a telescope. If it is short (up to 7), high magnification It will be harder to get. A long focal length starts at 8 units; such a telescope will magnify more, but the viewing angle will be smaller.
This means that to observe the Moon and planets, a higher magnification is needed. Aperture (as important parameter for the amount of light) is important, but these objects are already quite bright. But for galaxies and nebulae, it is the amount of light and aperture that are most important. - What is the magnification of a telescope?
Telescopes visually magnify an object so much that you can see details on it. The magnification will show how much you can visually enlarge something at which the observer’s gaze is directed.
The magnification of a telescope is largely limited by its aperture, that is, by the boundaries of the lens. In addition, the higher the magnification of the telescope, the darker the image will be, so the aperture must be large.
The formula for calculating magnification is: F (lens focal length) divided by f (eyepiece focal length). One telescope usually comes with several eyepieces, and the magnification ratio can thus be changed. - What can I see with a telescope?
This depends on telescope characteristics such as aperture and magnification.
So:
aperture 60-80 mm, magnification 30-125x - lunar craters from 7 km in diameter, star clusters, bright nebulae;
aperture 80-90 mm, magnification up to 200x - phases of Mercury, lunar grooves 5.5 km in diameter, rings and satellites of Saturn;
aperture 100-125 mm, magnification up to 300x - lunar craters from 3 km in diameter, clouds of Mars, stellar galaxies and nearby planets;
aperture 200 mm, magnification up to 400x - lunar craters from 1.8 km in diameter, dust storms on Mars;
aperture 250 mm, magnification up to 600x - satellites of Mars, details of the lunar surface from 1.5 km in size, constellations and galaxies. - What is a Barlow lens?
Additional optical element for a telescope. In fact, it increases the telescope's magnification several times, increasing the focal length of the lens.
The Barlow lens does work, but its capabilities are not unlimited: the lens has a physical limit to its useful magnification. After overcoming it, the image will really become larger, but the details will not be visible, only a large cloudy spot will be visible in the telescope. - What is a mount? Which mount is better?
A telescope mount is the base on which the tube is mounted. The mount supports the telescope, and its specially designed mount allows you not to rigidly mount the telescope, but also to move it along different trajectories. This will be useful, for example, if you need to monitor the movement of a celestial body.
The mount is just as important for observing as the main part of the telescope. A good mount should be stable, balance the pipe and fix it in the desired position.
There are several types of mounts: azimuth (lighter and easier to set up, but difficult to keep the star in the field of view), equatorial (more difficult to set up, heavier), Dobson (a type of azimuth for floor installation), GoTo (self-guided telescope mount, you just need to enter the target ).
We do not recommend the equatorial mount for beginners: it is difficult to set up and use. Azimuthal for beginners - just right. - There are Maksutov-Cassegrain and Schmidt-Cassegrain mirror-lens telescopes. Which one is better?
From the point of view of application, they are approximately the same: they will show both near space, and distant, and ground objects. The difference between them is not so significant.
Due to their design, Maksutov-Cassegrain telescopes do not have side glare and their focal length is longer. Such models are considered preferable for studying planets (although this statement is practically disputed). But they will need a little more time for thermal stabilization (starting to work in hot or cold conditions, when you need to equalize the temperature of the telescope and the environment), and they weigh a little more.
Schmidt-Cassegrain telescopes will require less time for thermal stabilization and will weigh a little less. But they have side glare, a shorter focal length, and less contrast. - Why are filters needed?
Filters will be needed for those who want to take a closer look at the object of study and examine it better. As a rule, these are people who have already decided on a goal: near space or distant space.
There are planetary filters and deep space filters, which are optimal for studying the target. Planetary filters (for planets of the Solar System) are optimally selected in order to view a particular planet in detail, without distortion and with the best contrast. Deep sky filters (for deep space) will allow you to focus on a distant object. There are also filters for the Moon, so that you can view the earth’s satellite in all detail and with maximum convenience. There are also filters for the Sun, but we would not recommend observing the Sun through a telescope without proper theoretical and material preparation: for an inexperienced astronomer there is a high risk of vision loss. - Which manufacturer is better?
From what is presented in our store, we recommend paying attention to Celestron, Levenhuk, Sky-Watcher. There are simple models for beginners and separate additional accessories. - What can you buy in addition to the telescope?
There are options, and they depend on the wishes of the owner.
Light filters for planets or deep space - for better results and image quality.
Adapters for astrophotography - for documenting what you were able to see through the telescope.
A backpack or carrying bag - for transporting the telescope to the observation site, if it is remote. The backpack will protect fragile parts from damage and not lose small items.
Eyepieces - the optical designs of modern eyepieces differ; accordingly, the eyepieces themselves differ in price, viewing angle, weight, quality, and most importantly - focal length (and the final magnification of the telescope depends on it).
Of course, before making such purchases, it is worth checking whether the add-on is suitable for the telescope. - Where should you look through a telescope?
Ideally, to work with a telescope, you need a place with a minimum of lighting (city illumination from street lamps, illuminated advertising, light from residential buildings). If there is no known safe place outside the city, you can find a place within the city, but in a fairly dimly lit place. Clear weather will be required for any observations. It is recommended to observe deep space during the new moon (give or take a few days). A weak telescope will need a full moon - it will still be difficult to see anything further than the Moon.
Basic criteria when choosing a telescope
| Optical design. Telescopes come in mirror (reflector), lens (refractor) and mirror-lens types. | |
| Lens diameter (aperture). The larger the diameter, the greater the telescope's aperture and its resolution. Moreover, the more distant and dim objects can be seen through it. On the other hand, diameter greatly influences the dimensions and weight of a telescope (especially a lens one). It is important to remember that the maximum useful magnification of a telescope cannot physically exceed 1.4 times its diameter. Those. with a diameter of 70 mm, the maximum useful magnification of such a telescope will be ~98x. |  |
| Focal length— how far the telescope can focus. A long focal length (long focal length telescopes) means higher magnification, but a smaller field of view and aperture ratio. Suitable for detailed viewing of small, distant objects. A short focal length (short-focus telescopes) means low magnification but a large field of view. Suitable for observing extended objects such as galaxies and astrophotography. |  |
Mount is a method of attaching a telescope to a tripod.
|
Pros and cons of optical circuits
Long-focus achromat refractors (lens optical system)
Short-focus achromat refractors (lens optical system)
Long-focus reflectors (mirror optical system)
Short throw reflectors (mirror optical system)
Mirror-lens optical system (catadioptric)
Schmidt-Cassegrain (a type of mirror-lens optical design)
Maksutov-Cassegrain (a type of mirror-lens optical design)
What can you see through a telescope?
Aperture 60-80 mm
Lunar craters from 7 km in diameter, star clusters, bright nebulae.
Aperture 80-90 mm
Phases of Mercury, lunar grooves 5.5 km in diameter, rings and satellites of Saturn.
Aperture 100-125 mm
Lunar craters from 3 km to study the clouds of Mars, hundreds of star galaxies, nearby planets.
Aperture 200 mm
Lunar craters 1.8 km, dust storms on Mars.
Aperture 250 mm
Satellites of Mars, details of the lunar surface 1.5 km, thousands of constellations and galaxies with the ability to study their structure.
OPTICAL TELESCOPE- used to obtain images and spectra of space. objects in optical range. The radiation of objects is recorded using photographs. or TV cameras, electro-optical converters, charge-coupled devices. The effectiveness of O. t. is characterized by extreme magnitude, achievable on a given telescope for a given signal-to-noise ratio (accuracy). For weak point objects, when the noise is determined by the background of the night sky, it depends mainly. from attitude D/, Where D- aperture size O. t., - ang. diameter of the image it produces (the larger D/, the greater, all other things being equal, is the limiting magnitude). Working in optimal O. t. conditions with a mirror diam. 3.6 m has a maximum magnitude of approx. 26 T with an accuracy of 30%. There are no fundamental restrictions on the maximum stellar magnitude of terrestrial stars.
Astr. O. t. was invented by G. Galilei in the beginning. 17th century (although he may have had predecessors). His O. t. had a scattering (negative) eyepiece. Approx. at the same time, J. Kepler proposed O. t. with positive. an eyepiece that allows you to install a cross of threads in it, which significantly increased the accuracy of sighting. Throughout the 17th century. astronomers used optical telescopes of a similar type with a lens consisting of a single flat-convex lens. With the help of these orbitals, the surface of the Sun (spots, faculae) was studied, the Moon was mapped, and the satellites of Jupiter and the rings and satellites of Saturn were discovered. In the 2nd half. 17th century I. Newton proposed and manufactured an optical lens with a metal lens. parabolic mirrors (reflector). With the help of a similar O. t. U. Herschel discovered Uranus. Progress in glass melting and optical theory. systems made it possible to create in the beginning. 19th century achromatic lenses (see Achromat).ABOUT. i.e. with their use (refractors) they had a relatively short length and gave a good image. With the help of such optical telescopes, distances to the nearest stars were measured. Similar tools are still used today. The creation of a very large (with a lens diameter of more than 1 m) lens refractor turned out to be impossible due to the deformation of the lens under the influence of its own. weight. Therefore, in con. 19th century The first improved reflectors appeared, the lens of which was a concave parabolic mirror made of glass. shape, coated with a light-reflecting layer of silver. With the help of similar O. t. in the beginning. 20th century Distances to nearby galaxies were measured and cosmological discoveries were made. redshift.
The basis of optical technology is its optics. system. Ch. mirror - concave (spherical, parabolic or hyperbolic). Parabolic the mirror builds a good image only on optical. axis, hyperbolic - does not build it at all, so lens correctors are used that increase the field of view (Fig., A). Optical option system is the Cassegrain system: a beam of converging rays from Ch. parabolic the mirror is intercepted to the focus by a convex hyperbolic. mirror (Fig. b). Sometimes this focus is carried out with the help of mirrors into a stationary room (coudet focus). Working field of view, within the optical range. modern system large O. t. builds undistorted images, does not exceed 1 - 1.5°. Wider-angle O. t. are performed according to the Schmidt or Maksutov scheme (mirror-lens O. t.). In O. t. Schmidt correction. the plate is aspherical. surface and is placed at the center of curvature of the spherical. mirrors Maksutov systems have aberrations (see. Aberrations of optical systems)ch. spherical mirrors are corrected by a meniscus with a spherical surfaces. Diameter mirror-lens mirrors O. t. no more than 1.5 - 2 m, field of view up to 6°. The material from which O. t. mirrors are made has low thermal properties. coefficient expansion (TCR) so that the shape of the mirrors does not change when the temperature changes during observations.
Some optical designs of large modern reflectors: A- direct focus; b- Cassegrain trick. A- main mirror, IN- focal surface, arrows show the path of rays.
Optical elements of the optics are fixed in the optics tube. To eliminate decentering of the optics and prevent deterioration in image quality when the pipe is deformed under the influence of the weight of the optics parts, the so-called. compensation pipes type that do not change the direction of the optical fiber when deformed. axes
Installation (mounting) of the O.T. allows you to point it at a selected space object. object and accurately and smoothly accompany this object in its daily movement across the sky. The equatorial mount is widespread: one of the axes of rotation of the O. t. (polar) is directed towards the celestial pole (see. Astronomical coordinates), and the second is perpendicular to it. In this case, the object is tracked in one motion - rotation around the polar axis. With an azimuth mount, one of the axes is vertical and the other is horizontal. The object is tracked by three movements simultaneously (according to a program specified by the computer) - rotations in azimuth and altitude and rotation of the photographic plate (receiver) around the optical lens. axes An azimuthal mount makes it possible to reduce the mass of the moving parts of the pipe, since in this case the pipe rotates relative to the gravity vector in only one direction. O.T. mount bearings provide low static friction. Usually hydrostatic is used. bearings: rotation axis O.T. float on thin layer oil supplied under pressure.
O. t. installed in special. towers. The tower must be in thermal equilibrium with environment and with a telescope. O.t., intended for observations of the Sun, are installed in high towers - to reduce the influence of turbulence near the soil heated by the Sun, which noticeably worsens the image quality. Raising an optical telescope intended for night observations to a height of 10–20 m does not improve image quality (as was previously assumed).
Modern O. t. can be divided into four generations. The 1st generation includes reflectors with a main glass (TKR7 x 10 -6) parabolic mirror. shapes with a thickness to diameter ratio (relative thickness) of 1/8. Focuses - direct, Cassegrain and coude. The pipe - solid or lattice - is made according to the principle of max. rigidity. Bearings are usually ball bearings. Examples: 1.5- and 2.5-meter reflectors of the Mount Wilson Observatory (USA, 1905 and 1917).
O. t. of the 2nd generation is also characterized by parabolic. Ch. mirror. Focuses - direct with corrector, Cassegrain and coude. The mirror is made of pyrex (glass with TCR reduced to 3 x 10 -6), relates. thickness 1/8. Very rarely the mirror was made lightweight, that is, it had voids on the back side. The pipe is lattice, the principle of compensation is implemented. Ball or hydrostatic bearings. Examples: 5-meter reflector of the Mount Palomar Observatory (USA, 1947) and 2.6-meter reflector of the Crimean Astrophysics. observatory (USSR, 1961).
O. t. 3rd generation began to be created at the end. 60s They are characterized by optical scheme with hyperbolic Ch. mirror (the so-called Ritchie-Chretien scheme). Focuses: direct with corrector, Cassegrain, coude. Mirror material - quartz or glass-ceramic (TKR 5 x 10 -7 or 1 x 10 -7), relative. thickness 1 /
8. Compensation pipe schemes. Hydrostatic bearings. Example: 3.6-meter reflector of the European Southern Observatory (Chile, 1975).
O. t. 4th generation - instruments with a mirror dia. 7 - 10 m; They are expected to enter service in the 90s. They involve the use of a group of innovations aimed at meaning. reducing the weight of the tool. Mirrors are made of quartz, glass-ceramic and, possibly, pyrex (lightweight). Relates. thickness less than 1/10. Compensation pipe. The mount is azimuth. Hydrostatic bearings. Optical scheme - Ritchie - Chretien.
The world's largest telescope is the 6-meter telescope installed in the Special. astrophysics observatory (SAO) of the USSR Academy of Sciences in the North Caucasus. The telescope has a direct focus, two Nasmyth focuses and a coude focus. The mount is azimuth.
A certain perspective is available in O. t., consisting of several. mirrors, the light from which is collected in a common focus. One of these O. t. operates in the USA. It consists of six 1.8-meter parabolics. mirrors and the collecting area is equivalent to a 4.5-meter O. t. The mount is azimuthal.
Solar telescopes are characterized by very large spectral equipment, so the mirrors and spectrograph are usually made motionless, and the light of the Sun is applied to them by a system of mirrors called a coelostat. Diameter modern solar O. t. is usually 50 - 100 cm. Small highly specialized. solar instruments are made in the form of conventional refractors. It is planned to create a solar O. t. dia. 2.5 m.
Astrometric O. t. (intended to determine the positions of space objects) are usually small in size and higher. mechanical stability. O.t. for photography astrometry have special. lenticular lenses and equatorial mount. Passage instrument, meridian circle, photogr. anti-aircraft tube and a number of other astrometric. O. t. are not intended for tracking the daily movement of objects. Their equipment records the passage of an object through an optical lens. the axis of the instrument, the position of the cut relative to the meridian and vertical is known.
To eliminate the influence of the atmosphere, it is planned to install O. t. in space. devices.
Telescope structure
In the 20th century, astronomy made many steps in studying our Universe, but these steps would have been impossible without the use of such complex instruments as telescopes, the history of which goes back hundreds of years. The evolution of the telescope took place in several stages, and I will try to talk about them.
Since ancient times, humanity has been drawn to find out what is there, in the sky, beyond the Earth and the invisible to the human eye. The greatest scientists of antiquity, such as Leonardo da Vinci, Galileo Galilei, attempted to create a device that would allow one to look into the depths of space and lift the veil of mystery of the Universe. Since then, many discoveries have occurred in the field of astronomy and astrophysics. Every person knows what a telescope is, but not everyone knows how long ago and by whom the first telescope was invented, and how it was designed.
A telescope is a device designed to observe celestial bodies.
In particular, a telescope refers to an optical telescopic system not necessarily used for astronomical purposes.
There are telescopes for all ranges of the electromagnetic spectrum:
b optical telescopes
b radio telescopes
b x-ray telescopes
gamma-ray telescopes
Optical telescopes
A telescope is a tube (solid, frame or truss) mounted on a mount equipped with axes for pointing at and tracking the object of observation. A visual telescope has a lens and an eyepiece. The rear focal plane of the lens is aligned with the front focal plane of the eyepiece. Instead of an eyepiece, photographic film or a matrix radiation receiver can be placed in the focal plane of the lens. In this case, the telescope lens, from an optical point of view, is a photographic lens. The telescope is focused using a focuser (focused device). telescope space astronomy
According to their optical design, most telescopes are divided into:
b Lens (refractors or diopter) - a lens or lens system is used as a lens.
b Mirror (reflector or catoptric) - a concave mirror is used as a lens.
b Mirror-lens telescopes (catadioptric) - a spherical mirror is used as a lens, and a lens, lens system or meniscus serves to compensate for aberrations.
If you decide to buy a telescope, then you first need to understand what it is, what types there are, and which option is better to choose. This is what we will try to help you figure out.
If you decide to buy a telescope, then you first need to understand what it is, what types there are, and which option is better to choose. This is what we will try to help you figure out.
What is a telescope and why is it needed?
A telescope is a device that allows you to observe various celestial objects that are very distant from the observation point. Most often they are used to observe celestial bodies, but sometimes terrestrial objects are also examined with their help. Previously, they were very expensive, and only astronomers and ufologists could afford them. Today, devices of this kind are much more affordable, and even people can afford them. ordinary people. For example, the Astrologer store can help you buy them.
Optical telescopes
Different telescopes can operate in different ranges of the electromagnetic spectrum. The most common optical telescope. Almost all amateur telescopes today are optical. Such devices work with light. There are also radio telescopes, neutrino telescopes, gravitational telescopes, X-ray telescopes and gamma telescopes. However, all this applies to scientific equipment, which is not used in everyday life.
Types of telescopes
Optical telescopes, both professional and amateur, are divided into three types. The main criterion here is the telescope lens, or rather the principle by which it works. Various types You can find telescopes on the website www.astronom.ru.
Lens telescope
Lens refractors are called refractors, and they were the very first to be born. Their creator was Galileo Galilei. The advantage of such telescopes is that they require almost no special maintenance; they guarantee good color rendition and clear images. Such options are well suited for studying the Moon, planets, and double stars. It is worth noting that these devices are most suitable for professionals, since they are not so easy to use, and in addition they are quite large in size and high in cost.
Mirror telescope
Mirror reflectors are called reflectors. Their lenses consist only of their mirrors. Like a convex lens, a concave type mirror collects light at a specific point. If an eyepiece is placed at this point, the image can be seen. Among the advantages of such a telescope, the minimum price per unit of device diameter stands out, since large mirrors are much more profitable to produce than large lenses. They are also compact and easy to transport, while providing bright images with little distortion. Of course, DSLRs also have their drawbacks. This is additional time for thermal stabilization, lack of protection from dust and air, which can spoil the image.
Mirror-lens telescopes
They are called catadioptric and can use both lenses and mirrors. The advantage of such a telescope is its versatility, since with their help you can observe planets with the Moon, and deep space objects. They are also very compact and cost-effective. The only point is the complexity of the design, which complicates the independent adjustment of the device.