If you love astronomy and want to know much more about the universe, the time has come to think about which telescope to buy. To do this, you must not only know where to buy a telescope, but also know the different types that exist and which one is the most suitable for you, taking into account your needs, space, and budget, among other factors. Do you want to know how to choose a telescope? At oneHOWTO, we have the answer for you. Because buying an instrument like this should not be done at random, below, we give you the keys to acquiring the best product to continue investigating the universe from home. Are you ready to discover stars, constellations, planets, and satellites? Next, we talk about both telescopes for beginners and the professional astronomical telescope. You choose!
What you should know before choosing a telescope
A telescope is an optical instrument through which you can observe distant celestial bodies. Thus, this device gives us the possibility of visualizing what is at a great distance in a detailed way, since it offers us an enlarged image of the object in question that we are observing. The characteristics of the telescope make this instrument perfect for astronomy since it allows us to visualize celestial bodies and analyze them. But why was the telescope born? Before choosing a telescope, we encourage you to learn a little about its history.
History of the telescope
Its history is linked to different physical and optical discoveries. The first known date back to 1608 when Hans Lippershey, a German scientist, created a refracting telescope through a concave eyepiece lens and a convex objective. After some time of using this type of instrument, reflecting telescopes emerged with which the lenses were changed for mirrors that allowed the light to focus and improve the formation of images.
However, it was not until 1609 when the first astronomical telescope was registered by Galileo Galilei, who managed to observe various stars, Jupiter and the Moon. Thanks to him, the telescope was considered the basis for the development of astronomy, a science that studies celestial bodies.
Before choosing the right telescope for you, you need to know where to buy a telescope. You will find these instruments can be purchased both in specialized astronomy stores and on online pages. Also, you can find telescopes for beginners in large areas.
What type of telescope to buy
Before choosing a telescope you must be clear about what you are looking for and, for this, it is essential to ask yourself certain questions.
- What do I want to see?
- How much do I want to spend?
- Where am I going to use it?
- Am I sure I like astronomy?
Although the first three questions will allow you to select the type of telescope that best suits your needs, the last question is essential when making the decision to buy a telescope. It is an expensive instrument that not everyone can afford. For this reason, before making this expense, it is important to analyze how much you like astronomy and how much time you have to enjoy it, as this may also be a requirement when betting on one or the other. For example, you will not need a very powerful one if you are going to make short and sporadic observations, with a telescope for beginners or something a little more advanced but without becoming a professional you may have enough. Instead, you will need a professional astronomical telescope if you want to dedicate yourself to long-term observations. In this last case, you should know that there are powerful telescopes with special mounts and a multitude of accessories, batteries, tripods, counterweights, and mounts that will allow you to enjoy long nights of space observation.
On the other hand, when it comes to knowing the different types of telescopes, it is important to take into account the basic parameters that characterize them, such as the diameter of the objective, the focal length (distance between the mirror or lens and the focus where the eyepiece is located), the filter (allows the observed body to be obscured) and the magnification (number of times the apparent diameter of the visualized object can be multiplied). All of them are requirements that can define the purchase of a telescope.
There are many features to consider when wondering how to choose a telescope for beginners or a professional one. Therefore, it is important to have some clear aspects before making your purchase. Remember that the first thing you must define is the use you are going to give your telescope. If you have just become interested in the subject, opt for a telescope for beginners, but if you have already taken your first steps and want to expand your astronomical knowledge, you can broaden your horizons and opt for a professional astronomical telescope. Once you are clear about your needs, take note of the following factors that may determine your choice.
Telescope Optical Design
There are many types of telescopes and you can easily differentiate them by their optical design, which can be refractor, reflector, or catadioptric. Although they may seem like words from another planet, they are very simple concepts that will allow you to choose the best telescope for you, since the optical design directly influences any other feature or benefit of the telescope itself.
- Refractor: This is a telescope that uses a lens, or a combination of lenses, through which light is collected and focused. It is an easy-to-use telescope with good performance and a sharp image. They also do not require maintenance. However, their aperture is smaller and they tend to be more expensive, as cheaper refractors tend to have poor quality lenses. It is the telescope for terrestrial observation par excellence, although they are also good for observing planets.
- Reflector: This telescope is made up of two mirrors that reflect light from one to the other until it reaches the eyepiece. The advantage of this topology is that they are much cheaper than refractors, have a larger aperture, and adapt perfectly to the ambient temperature, which makes them perfect for beginners in astronomical observation. However, the quality is lower and they require more maintenance. Thanks to their opening they are ideal for observing the deep sky such as galaxies or nebulae.
- Catadioptric: they combine lenses and mirrors which results in a large focal length in a short tube. It is a type of telescope that is compact and easy to motorize, store, transport, and maintain. A true off-roader! In addition, they are perfect for both planetary and deep-sky observing. Its main disadvantage is that its price is the highest and that, being so versatile, it may not overcome the strengths of its competitors.
Opening
It is one of the most important aspects when choosing a telescope. The aperture is the diameter of the lens, the part through which light enters. The size of the objective is usually expressed in millimeters and you should know that the larger the diameter, the greater the amount of light that will enter through the telescope, which translates into much sharper, more precise, and higher quality images.
Aperture ranges for a beginner telescope are from 80mm to 150mm, while professional astronomical telescopes can have an aperture diameter of 300mm.
Use and comfort
Undoubtedly, your experience with the telescope should also be a fundamental factor when making your purchase. In this sense, there are certain characteristics that directly influence the use and comfort of this instrument.
- Mount: The mount is where the telescope mounts to the tripod and helps stabilize the telescope. The most common are the altazimuth mount, used in telescopes for terrestrial observation and basic astronomical telescopes, and the equatorial mount, which is more expensive, heavy, and difficult to handle, which is why they are used by professionals and experts. Likewise, the mounts can be manual (cheaper and simpler) or motorized.
- Optical finder: it is an accessory that fits the telescope and allows you to locate the object you want to locate. It usually has low magnifications, between 6x and 8x, but its aperture is usually large. The larger the finder aperture, the easier it is to detect dimly lit objects.
- Weight and size: basic for the use of the telescope and its comfort when transporting it. You must take into account your needs and physical form.
Telescope price
Your budget is one of the keys when buying a telescope. As you know, it is not a cheap instrument and, in addition, the range of prices and features may vary depending on your own needs. Setting your budget limit will help you choose the best telescope for you. The options are as follows:
Telescopes under €200
This is the most difficult option to achieve, especially if you need to get started in astronomy in a committed way because in a short time you will need a more complete telescope. However, if you do not want to spend more than €200, we recommend you start by buying good binoculars that allow you to discover the most important stars and with which you learn to move freely through the sky.
Telescopes up to €500
Between €200 and €500, you can find both good and bad telescopes. However, if you want to get started in astronomy, it is a reasonable price to start your investment as a beginner such as the Dobson 200/1200 or the Startravel 120/600.
Telescopes up to €800
The price range of up to €800 is one of the most interesting, as it will allow you to find quality equipment among a wide variety of models. Within this range, you can take into account both your tastes and your preferences and interests when choosing the perfect option for you.
Telescopes from €1,000
From €1,000, a great universe of possibilities opens up before you. These are telescopes with much more complete mounts and accessories and that are designed for much more detailed astronomical observation. Telescopes in this price range will allow you to discover any corner of the universe. These include devices such as the Dobson SkyWatcher 300/1500 telescope with or without GoTo, the Nextar Evolution 8″, or the 200/1000 reflector telescope with HEQ5 mount.
Telescope focal length and ratio
Another characteristic of a telescope is the focal length, that is, the distance that light travels from when it enters the objective until it reaches the eyepiece. This factor, which is measured in millimeters, is usually printed on the telescope itself and can directly influence the focal ratio and magnification.
Focal ratio is a term you may see in the description of a telescope. It is a number that expresses the aperture with respect to the focal length, that is, a calculation obtained by dividing the focal length of the telescope by the aperture. Generally, this number is written preceded by “f/”. The smaller the “f/” number, the smaller the magnification, the wider the field of view, and the brighter the image.
- From f/4 to f/5 is the best focal ratios if you want to observe wide spaces and the deep sky (galaxies, nebulae…).
- From f/6 to f/10 are the intermediate focal ratios characterized by their versatility.
- From f/11 to f/15 these are perfect focal ratios for observing planets.
Increase
Magnification refers to the power of the telescope and how “close” you are to the object while observing. It is calculated by dividing the focal length by the eyepiece focal length, and the number is usually written with a final “x” (eg: 60x, 48x, 12x…). The longer the focal length of the telescope and the shorter the focal length of the eyepiece, the more magnification you will have. When choosing a telescope you should be careful not to have too many magnifications, as they could be counterproductive: loss of brightness and sharpness, difficulty focusing… Therefore, it is also important to take this aspect into account before buying a telescope.
We hope that now you have an easier time choosing a telescope to enjoy astronomy. We also recommend reading these other OneHOWTO articles about How to clean a telescope lens and Tips and tricks for seeing the stars.
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