Buying a Telescope for Planets and Stars: How to Choose

For observing planets and stars, choose a telescope not by its maximum magnification, but by the combination of aperture, optical design, and a stable mount. Detailed planetary observing calls for a sharp image and easy tracking, while observing the stars requires light-gathering ability; the right choice depends on where and how you plan to observe.

Buying a telescope for planets and stars is not easy: there is no one-size-fits-all model that is equally convenient for every purpose and observing condition. Let’s look at which features really affect what you can see and how to choose an instrument you’ll enjoy using.

• 70–90 мм Aperture for the Moon and your first planetary observations
• 100–130 мм Aperture offering more room for further exploration
• около 200 мм Aperture of models for regular trips outside the city to observe nebulae, galaxies, and star clusters

What aperture should you choose for the Moon, planets, and deep-sky objects?

An aperture of 70–90 mm is suitable for the Moon and your first planetary observations; for more room to grow, consider 100–130 mm; and if you regularly travel outside the city to observe nebulae, galaxies, and star clusters, look at a model around 200 mm. Aperture is the diameter of the main lens or mirror: it determines how much light the telescope collects.

First, decide what you want to observe

Your choice of aperture depends on what you want to observe and how ready you are to expand your interests. The difference between these ranges is not a promise of a particular view through the eyepiece, but a difference in light-gathering capability.

• 70–90 mm — an option for the Moon and your first planetary observations.
• 100–130 mm — more scope to explore further and observe fainter objects.
• Around 200 mm — an aperture for those who regularly travel outside the city to observe nebulae, galaxies, and star clusters.

A larger aperture calls for suitable observing conditions

A telescope around 200 mm makes sense if you genuinely plan to travel outside the city and observe deep-sky objects; that aperture is not essential for the Moon or getting started with planetary observing. When choosing between 100–130 mm and around 200 mm, weigh the extra light-gathering capacity against your main observing plans: fainter objects require not only a larger lens or mirror, but also a suitable observing location.

Why are refractors and Maksutov-Cassegrains convenient as first telescopes?

A refractor makes a convenient first telescope thanks to its straightforward optical design and intuitive operation, while a Maksutov-Cassegrain is a good choice when compact size is especially important; with either design, consider the aperture and the stability of the mount.

Refractor

A refractor uses a lens to collect light, so models with an aperture of 70–90 mm are worth considering for your first observations of the Moon, planets, and stars. On a simple altazimuth mount, the instrument moves vertically and horizontally, making this a beginner-friendly setup that does not require learning complicated controls.

Maksutov-Cassegrain

A Maksutov-Cassegrain is a compact option for anyone who wants a telescope that takes up less space. But the optical design alone does not settle the choice: aperture determines how much light the instrument collects, and the mount needs to hold it steady while you observe.

• 70–90 mm refractor: an option for getting started with the night sky; a simple altazimuth mount makes pointing and tracking an object easier.
• Maksutov-Cassegrain: choose one if compact dimensions are a priority, and check the aperture and mount stability separately.

Which mount should you choose for comfortable observing?

For your first telescope, choose a simple altazimuth mount. If finding objects on your own seems difficult, consider a model with GOTO. An altazimuth mount moves up and down and from side to side, making it easier for beginners to understand how to point the tube. This type of mount is common on inexpensive telescopes, but the stability of each model should be assessed separately.

• Altazimuth mount without GOTO. Suitable for manual pointing and does not require you to learn automated controls. When checking a particular telescope, pay attention to how securely the mount holds the tube and how easy it is to use.
• Mount with GOTO. This feature helps automatically locate selected objects and can be useful if finding stars and planets on your own is difficult. It does not mean the telescope will point itself automatically without setup and operation.

What to check with GOTO

Before buying, check whether the GOTO system is included: a mention of the feature in the product description is not enough to establish what comes in the box. Also check that the controls are compatible with your chosen telescope model. Compare not only whether automated searching is available, but also the mount’s stability: easier pointing cannot make up for a wobbly support.

Which telescope features are worth paying for?

It is worth paying for telescope features when they suit your observing conditions: an aperture of 70–90 mm is suitable for beginners, around 200 mm is especially appealing for regular trips outside the city, and GOTO is useful for anyone who wants help finding objects.

• Aperture: Telescopes of 70–90 mm are suitable for your first observations of the Moon and planets. The 100–130 mm range leaves more room to develop your interests, while around 200 mm is worth considering if you are prepared to travel outside the city to observe nebulae, galaxies, and star clusters.
• GOTO: It may be worth paying extra for automated object finding if navigating the sky on your own is difficult or you want to locate objects faster. If you are happy to find them yourself, this feature is not essential.
• Mount: Assess the included mount and how easy it is to point the telescope. A wobbly mount gets in the way of observing, and extra telescope features will not fix that.

Get ready to find objects

Before buying, choose a star atlas or a planetarium program for your PC: both can help you work out where to find the objects you are interested in. These tools are useful with a simple altazimuth mount as well as with a GOTO-equipped telescope: they help you navigate the sky but do not replace a stable support or a suitable aperture.

Which claims in telescope descriptions can mislead beginners?

Claims of enormous magnification, GOTO’s all-purpose capabilities, and the superiority of large aperture alone can mislead beginners: choose based on the combination of aperture, optics, mount, and observing goals. Magnification does not indicate how much light an instrument collects, and automated searching does not overcome the limitations of an optical design. For example, compare a simple refractor on an altazimuth mount with a compact Maksutov-Cassegrain: what matters is not the marketing language, but how well the design suits your conditions.

When a large aperture is not the best first choice

An aperture around 200 mm is especially appropriate for regular trips outside the city to observe nebulae, galaxies, and star clusters, but it does not guarantee ease of use. If compactness and a simple introduction to observing are important, consider a refractor on an altazimuth mount or a Maksutov-Cassegrain; either way, decide in advance what you plan to observe.

• For the Moon and your first planetary observations: consider an aperture of about 70–90 mm.
• For room to grow: the 100–130 mm range offers more possibilities.
• For trips outside the city: models around 200 mm suit those planning to observe nebulae, galaxies, and star clusters.
• For easier object finding: GOTO helps you point at objects, but it does not replace suitable optics or make a telescope all-purpose.

A compact Maksutov-Cassegrain should not be considered weak just because of its small dimensions: this design can be convenient when storage and transport space are limited. However, you should still choose a suitable model based on your goals—planetary observing and finding distant objects call for different capabilities.

How should you prepare for your first observations after buying a telescope?

Prepare for your first observations by starting with the Moon and planets, choosing in advance how you will find objects, and checking that the telescope’s aperture suits your goals. For a first telescope, aim for 70–90 mm; this range is enough to get acquainted with the night sky.

• For the Moon and planets: choose a telescope with an aperture of 70–90 mm. If finding celestial objects is difficult, consider a model with GOTO, an automated pointing system.
• For finding objects manually: prepare a star atlas or a planetarium program for your PC. These will help you navigate when searching for objects without GOTO.
• For trips outside the city: if you are interested in nebulae, galaxies, and star clusters, look at telescopes with an aperture around 200 mm. Before setting out, make sure your chosen model suits these goals.

What to prioritize

Your choice of telescope also depends on how you plan to observe: decide in advance what matters most to you—a compact body, easy pointing, or a large aperture. A compact model is easier to transport; GOTO simplifies finding objects; an aperture around 200 mm is intended for those interested in nebulae, galaxies, and star clusters. Match your priorities to your observing plans, not just to what you hope to see on your first night.

Frequently asked questions

Written byAglaya Vetluzskaya

Пишет о планетах и малых телах Солнечной системы: от геологии Марса и ледяных спутников до астероидов и комет. Сопоставляет данные миссий и наблюдений, объясняя, где заканчиваются подтверждённые факты и начинаются гипотезы.