Buying a telescope is not an easy task, if you don't know terms like focal ratio, magnification, or automatic focus, you will have problems about the telescope and especially technical matters. Therefore, before you finalize your purchase, you should familiarize yourself with the basics of the telescope. In the article 15 important things about the telescope that you should know, stay with us to find the answer to every question you have about the telescope.
- We know that telescopes make things look bigger, but what exactly do they do?
The main purpose of a telescope is to collect light. This feature enables you to see much fainter objects than you can see with the naked eye. Galileo described telescopes best: "They reveal the invisible."
２. When we buy a telescope, is it usable or does it need accessories?
Most telescopes marketed to beginners are complete systems. In other words, you can use the device as soon as you open the package and complete the setup process. Some high-end models are sold as "optical tube kits". This means that you are only buying the optics inside the tube and not the mount, tripod, or accessories that come with it.
Breakers usually require a star diagonal due to their design. The diagonal of the star bends the light of the target object by 90 degrees, thus making it easier to see objects that are overhead. The diagonal of the star is placed in the focuser of the telescope and the eyepiece is placed in the diagonal of the star. Most manufacturers supply a refracting telescope with a star diagonal.
- If we are interested in observing celestial objects, what telescope should we buy?
The first step is to learn as much as possible about telescopes: what types are available, what manufacturers sell them, and what features they have. If a particular model catches your eye, visit the manufacturer's website and read reviews. You may not understand everything discussed, but you will be familiar with telescope terminology. By doing this, you will understand what is important to observers when using a telescope. Read reviews to learn about optical and mechanical quality, ease of use (including portability), additional features, and most importantly, what objects the telescope shows best. The three main types of telescopes use a lens, a mirror, or a combination of both. Refractive models use a lens (a combination of at least two to four pieces of glass) as the primary means of gathering light. In contrast, reflective models use mirrors to collect and focus light. In a Newtonian reflecting telescope (the most common type), light is reflected from the primary mirror and hits a smaller, flat secondary mirror near the top of the tube. Then, the light is bent 90 degrees and enters the eyepiece through a small hole in the tube. Compound telescopes have a main mirror with a correcting lens in front of the tube. The main mirror has a simple and usually spherical structure. Although a spherical mirror introduces distortions in the observed image, a correcting lens bends the light before it hits the mirror. Schmidt-Casgrain and Maksotov-Casgrain models are famous combined telescopes.
- Is it true that we should buy binoculars before a telescope?
no The view through binoculars is often frustrating for beginners, especially if light pollution is high. However, high-quality binoculars are valuable viewing accessories. Large star clusters, the Milky Way and the Moon look great in binoculars.
- What is the size of small, medium and large telescopes?
These terms are not standard, but in general, when we refer to a small telescope, we mean a telescope with an aperture (the size of the lens or mirror) of less than 4 inches. Average telescopes have an aperture of 4 to 10 inches and are used by most beginning astronomers. One of the most popular models is the 8-inch Schmidt-Casgrain Finally, any telescope with a lens or mirror larger than 10 inches is considered large. Larger telescopes are used today than ever before, largely due to the introduction of Dobsonian mounts. Newtonian reflecting telescopes with alt-az Dobsonian mounts cost and weigh significantly less than large instruments with motorized equatorial mounts. - Is a bigger telescope better? What are the real benefits of large telescopes?
The larger the diameter of the telescope, the more light it collects. For example, a 4-inch model is great for observing the planets, moon, and binary stars. However, this size is a bit small for viewing deep sky objects such as nebulae, star clusters and galaxies. An 8-inch model (no matter what type) takes you to a whole new dimension of vision. The objects you see with this device will have more details. However, if you are interested in astronomy, even this size will not be enough for you. This is known among novice astronomers as aperture fever. If you started with a quality 2.4" telescope and now have a 4" refractor or Schmidt-Cassegrain 8, you may be dreaming of a 20" telescope. - Is "achromat" different from "apochromat"? What do these terms mean? Both terms refer to lens systems used in refracting telescopes. Achromat is a two-lens system. Apochromats may also use two lenses but are more likely to have three or four lenses. The main difference between an achromatic and apochromatic telescope is the amount of extra color you'll see on bright objects. Additive color isn't color added to what you're viewing, but usually appears as a purple fringing at one edge of the object. Apochromatics provide an image essentially free of excess color. In contrast, with achromatic models you'll see extra color on bright objects like Jupiter, Venus, and the Moon. However, many people can ignore the extra color. Apochromatics are always significantly more expensive than similar achromatics.
- What is the first thing you should do after buying a new telescope?
Read the manual a few times and do it at home before setting up the telescope outside in the dark of night. In this way, you will become familiar with the location and function of each key, button and lever.
- Why are the objects we see through the telescope upside down?
Before the light collected by the telescope's main lens or mirror enters the eyepiece, it is rotated. Therefore, the image you see is upside down. A graticule (also known as an image corrector) re-rotates the image, but adding this accessory causes some light loss. Since the function of a telescope is to bring the maximum amount of light from an object to your eye, you don't want to lose light by rotating the image. Also, keep in mind that there are no ups and downs in space, and when viewing most objects you won't even notice they are upside down. f/4, f/10 or f/15 indicate the focal ratio of the telescope (f/ratio). Focal ratio is determined by dividing the focal length (the distance from the objective lens to the point where light is focused) by the aperture. Suppose a 6-inch telescope has a focal length of 36 inches. To find its focal ratio, you need to divide 36 by 6, which results in f/6. Aperture is usually measured in inches, but focal length is measured in millimeters. In this case, just multiply inches by 25.4. To find the magnification, simply divide the focal length of the telescope (fo) by the focal length of the eyepiece (fe). For example, if the focal length of your telescope is 1000 mm and you choose a 25 mm eyepiece, the magnification will be 40 times. Remember that magnification alone is not a good indicator of telescope quality. Magnification is determined by the eyepiece you use. Therefore, a low-quality telescope may have a weak eyepiece, but their combination will have great power. However, the zoomed-in image looks jumbled.
１０. Can a telescope be used to observe terrestrial objects?
Definitely! Many night observers (usually those who prefer refracting models due to size and portability issues) use their telescopes to watch birds or other natural phenomena. Also think about the images you have seen of sailors in past centuries. They almost always looked at the road ahead with a telescope.
１１. Why are telescopes expensive?
A good telescope is a combination of high quality optics, machining, electronics and mechanical controls. Such things are not cheap. To make mirrors or curved lenses, very expensive and high-precision machines are required. Some lenses consist of four separate elements, each with two optical surfaces. The larger the mirror or lens, the larger and stronger the tube, motor axis, and tripod must be.
１２. Is there a way to try different telescopes?
yes If you join a local astronomy club or society, you'll meet other people who enjoy astronomy as much as you do and are willing to share information and equipment. At public or private observation events, you can try different models
１３. Apart from high-quality optics, what is the most important thing in a telescope?
Even if you buy the best optics on the planet but put them on a small or poor quality mount, you won't be happy with your system. No telescope can operate in strong winds, but the weak mount transmits the vibrations of even a gentle breeze to the instrument.
The quality of the frame also affects the duration of the still image. This is the time interval between touching the device (for example to focus) and the image in the eyepiece becoming still. Strong headquarters reduces this time to a second or two. Conversely, if the headquarters is bad, it will take a long time for the image to stabilize. Therefore, before buying the headquarters, be sure to try it.
１４ Is a telescope equipped with a GoTo headquarters better?
If the GoTo HQ is installed and set up correctly, the on-board computer-controlled movement towards the target will save a lot of time. However, you need to know how to adjust the telescope and find some bright stars. Use the sky chart for convenience. Even experienced observers prefer the GoTo scopes because they eliminate the need to find the subject through bright stars.
- Does the telescope need electricity?
No, but its axis motor needs electricity. Most motors use direct current, which means you can use a battery or an adapter.
Types of telescopes
The three main types of telescopes use a lens, a mirror, or a combination of both. Refractive models use a lens (a combination of at least two to four pieces of glass) as the primary means of gathering light.
In contrast, reflective models use mirrors to collect and focus light. In a Newtonian reflecting telescope (the most common type), light is reflected from the primary mirror and hits a smaller, flat secondary mirror near the top of the tube. The light is then bent 90 degrees and enters the eyepiece through a small hole in the tube.
Compound telescopes have a main mirror with a correcting lens in front of the tube. The main mirror has a simple and usually spherical structure. Although a spherical mirror introduces distortions in the observed image, a correcting lens bends the light before it hits the mirror. Schmidt-Casgrain and Maksotov-Casgrain models are famous combined telescopes.
Types of telescope headquarters
The equatorial center moves in two planes and one axis is towards the North Celestial Pole (NCP). The NCP is a point in the northern sky close to the Pole Star (North Star). With the help of the motor axis, you can align the headquarters with the NCP and the object you are viewing will remain in the field of view. If you plan to do long exposure astrophotography or digital imaging, an equatorial mount is essential.
The alt-az mount moves the telescope horizontally and vertically. A camera tripod is a good example of an alt-az mount. It may be difficult to distinguish the headquarters of alt-az from the tropics. The difference is that the base of the equatorial fork aligns with the NCP. Fork mounts are popular in compound telescopes. Also, most modern observatories use equatorial fork stations.
The Dobsonian mount is a type of alt-az designed specifically for Newtonian reflecting telescopes. The design of the headquarters is simple and includes a rotating base and a place for the telescope tube. If you want, you can easily build a headquarters.