The Ultimate Guide to Choosing the Right Telescope

If you’ve ever gazed up at the night sky and thought, “I need to see that up close!”—welcome, fellow stargazer, you’re in the right place. (And if you haven’t thought about that yet, don’t worry, you will soon. It’s a slippery slope from curiosity to I-need-a-bigger-scope syndrome.)

Telescopes come in many shapes, sizes, and price tags! Each type helps you unravel the universe in its own special way. Whether you’re a newcomer to astronomy or a seasoned stargazer, choosing the right telescope will save you a ton of frustration and money.

From spotting the Moon’s craters to hunting distant galaxies, the right telescope makes all the difference. Get it right, and you’ll revel in cosmic wonders; get it wrong, and you’ve got yourself a pricey coat rack.

This guide will help you navigate the many telescope options on the market. I’ll explain how they work, their best uses, and the features and accessories that will take your starry adventures to the next level.

Whether you're buying your first telescope or want to upgrade, this guide will help you make an informed choice.

Getting started: Understanding the terminology

Before you begin shopping, it’s crucial to understand how telescopes work and what all the technical specifications mean. A telescope isn’t just a fancy tube with lenses or mirrors (okay, well it kind of is). But it’s also an invaluable tool that collects and focuses light to help you see distant objects in stunning detail. Knowing the basics will make it much easier to choose the right telescope for your needs. Think of it as learning the lingo before stepping into a new hobby. It saves you time and money and helps you avoid buying something that doesn’t suit your stargazing goals.

Basic telescope terms

• Aperture: The diameter of the main lens or mirror (in millimetres or inches). Larger apertures collect more light, giving brighter and more detailed images.

• Focal Length: The distance (in millimetres) from the primary lens or mirror to where it brings light to focus. It affects magnification and the field of view.

• Focal Ratio (f/number): The ratio of the focal length to the aperture (e.g., F/10). Lower numbers mean a wider field of view and faster imaging, while higher numbers are better for detailed, high-magnification views.

• Magnification: Calculated by dividing the telescope’s focal length by the eyepiece’s focal length. Higher magnification isn’t always better—it depends on seeing conditions and the telescope’s capabilities.

• Mount: The structure that supports the telescope and allows movement. Mounts come in two main types: Alt-Azimuth (simple up-down, left-right) and Equatorial (aligned with Earth’s rotation for tracking objects).

Optical terms

Terms for telescope-related accessories

Astrophotography-related terms

Performance metrics terms

Now that you’ve cracked the code on all the fancy astro-terms, let’s dive into the cool gadgets that make it all happen. Time to take a closer look at the different types of telescopes that help us peek into the universe!

Types of telescopes: What they are and how they work

Refractor Telescopes

Refractor telescopes are the oldest telescope design, first popularised in the 17th century by Hans Lippershey and Galileo. These instruments use lenses to gather and focus light, making them a simple, reliable, and low-maintenance choice for wide-field astrophotography and visual observing.

Refractors focus light through a large convex lens, known as the objective lens, at the front of the tube. The light rays bend as they pass through the lens and converge at a focal point at the eyepiece or camera.

An internal diagram of how a refracting telescope works. Image credit Let's Talk Science.

Types of Refractor Telescopes

There are two main types of refractor designs:

Achromatic Refractors

Achromatic refractors use a doublet lens system, combining two glass elements to minimise chromatic aberration by bringing red and blue wavelengths closer together. This results in clearer views compared to single-lens telescopes, which is why they’re a popular choice for beginners. That said, some colour fringing may still appear around bright objects like planets or stars.

I love how affordable and easy to find these telescopes are - perfect for casual stargazing or as a first telescope. They offer fantastic value for the price, though they don’t quite match the performance of more advanced designs. If you’re after simplicity and affordability over perfection, an achromatic refractor is a good choice.

Apochromatic (Apo) Refractors

Apochromatic refractors take optical performance up a notch with their triplet or quadruplet lens systems made from specialised glass. These lenses correct chromatic aberration across red, green, and blue wavelengths, virtually eliminating colour fringing. The result? Clearer and sharper images that are perfect for astrophotographers and advanced observers. They’re brilliant for capturing detailed views of star clusters and deep-sky objects.

Yes, they’re pricier than achromatic refractors, but the exceptional image quality is well worth it if you’re chasing precision and clarity. The extra lenses make them heavier and less portable, though, so keep that in mind. Models from Sky-Watcher and the William Optics GT Series are fan favourites among serious hobbyists.

Achromatic refractors are ideal for those new to astronomy. They’re simple to use, require no mirror alignment (collimation), and provide excellent views of bright celestial objects.

What Are Refractors Best Used For?

Refractors are versatile telescopes, ideal for observing and photographing the Moon, the Sun (with proper solar filters), and deep-sky objects like nebulae and star clusters. Their smaller apertures (typically 60mm–150mm) and longer focal ratios (around F7) limit how much light they gather compared to reflectors (another type of telescope that uses mirrors), but they excel at delivering sharp, high-contrast views.

The aperture - the size of the main lens - determines how much light the telescope collects, while the focal ratio (the focal length divided by the aperture) affects image brightness. For telescopes with the same aperture, a lower focal ratio (e.g., F5) produces brighter images than a higher ratio (e.g., F7) by concentrating light into a smaller area.

While refractors aren’t the best choice for faint objects like distant galaxies, they’re perfect for crisp views of the Orion and Lagoon Nebula or detailed looks at planets and lunar craters. Their clarity and contrast make them a solid all-rounder for most observing and imaging needs.

Apochromatic refractors are a favourite among astrophotographers because of their exceptional optical quality and portability, which makes them perfect for quick grab-and-go sessions.

Pros and Cons of Refractor Telescopes

Pros:

• Robust design with no need for collimation.

• The sealed optical tube protects against dust and moisture.

• Delivers sharp, high-contrast views of planets and the Moon.

Cons:

• They can have a higher cost per inch of aperture compared to other telescope types.

• Limited aperture size reduces their effectiveness for faint deep-sky objects.

• Chromatic aberration may be an issue in lower-end achromatic models.

Which Brands Are Highly Recommended

For beginners, an achromatic refractor like the Sky-Watcher Evostar 90 offers excellent value and simplicity. Advanced users and astrophotographers may prefer an apochromatic triplet refractor like the Takahashi FSQ-106, renowned for its exceptional image quality and colour correction.

Note: Adding a dew shield is essential for humid climates to prevent moisture build-up on the objective lens.

Reflector Telescopes

Invented by Isaac Newton in 1668, reflector telescopes use mirrors instead of lenses to gather and focus light. This design eliminates chromatic aberration and offers large apertures at a fraction of the cost of refractors.

Reflectors use a primary mirror at the base of the tube to collect light, which is then focused onto a flat secondary mirror. The secondary redirects the light to an eyepiece or camera positioned on the side of the telescope. Unlike refractors, their open-tube design exposes the optics to the environment, so they need more maintenance.

An internal view of how a reflecting telescope works. Image credit Let's Talk Science.

Types of Reflector Telescopes

There are four main types of reflector telescopes:

Newtonian Reflectors

The most common and affordable type, Newtonians use a parabolic primary mirror and a flat secondary mirror to direct light to the eyepiece. They’re fantastic for deep-sky observing and imaging, thanks to their wide field of view and excellent light-gathering ability.

Dobsonian Reflectors

A subtype of Newtonian, Dobsonians pair a simple, stable mount with large apertures (200mm and above, though smaller desktop models are also available). They’re easy to use and deliver stunning views of deep-sky objects and planetary details, making them a favourite for visual observers.

Ritchey-Chrétien Telescopes (RCTs)

Using two hyperbolic mirrors, RCTs eliminate coma and spherical aberration for sharp, distortion-free images across a wide field. They’re prized by astrophotographers and professionals for their precision and are a go-to for observatories.

Cassegrain Telescopes

A Cassegrain telescope is a reflector design that uses a concave primary mirror and a convex secondary mirror to fold the optical path, allowing for a more compact tube. This folded light path is ideal for high-magnification observations of planets and stars while maintaining portability and excellent image quality.

What Are Reflectors Best Used For?

Reflectors excel at deep-sky observing and imaging, capturing faint galaxies, nebulae, and star clusters with ease. Their large apertures gather immense light, offering exceptional detail for both visual and astrophotography. They also shine at wide-field views, thanks to their ability to balance aperture and focal length.

Reflectors are perfect for beginners and intermediate users looking for powerful telescopes at a reasonable price. They’re ideal for astronomers interested in deep-sky objects or those keen on astrophotography. However, the open-tube design requires regular maintenance, like collimation and cleaning. If you’re okay with some upkeep, reflectors reward you with top-notch performance.

Pros And Cons of Reflecting Telescopes

Pros

• Affordable for large apertures.

• Outstanding light-gathering capability.

• Great for deep-sky observing and astrophotography.

Cons

• Some models require regular collimation.

• Open tube designs are vulnerable to dust and moisture.

• Some can be bulkier than small refractors.

Which Brands Are Highly Recommended

For beginners or those on a budget, the Sky-Watcher Heritage 130P and Orion StarBlast 6 are excellent choices. If you’re diving into astrophotography, consider a Dobsonian for its large aperture or an RCT for professional-quality imaging. Both offer exceptional performance for observing the cosmos or capturing stunning images of deep-sky and planetary wonders.

Catadioptric Telescopes

Catadioptric telescopes address the limitations of traditional reflector and refractor designs. First developed in the 1930s by Bernhard Schmidt and later improved upon by Dmitri Maksutov and others.

Catadioptric telescopes combine the best features of both reflectors and refractors. They use mirrors, typically spherical, aspherical, or parabolic, to collect and focus light. Depending on the telescope’s design, the primary mirror plays a key role in directing light toward a secondary mirror. This secondary mirror then reflects the light towards the eyepiece or camera. Lenses, such as a corrector plate or meniscus lens at the front, are used to correct optical aberrations like chromatic and spherical distortion, ensuring sharp, distortion-free images.

The light path is “folded” within the tube, allowing for a more compact design that is easier to transport than traditional reflectors or refractors. This design also enables a more manageable focal length, making catadioptric telescopes versatile for planetary and deep-sky observation. They are a popular choice among amateur astronomers and astrophotographers, thanks to their versatile design and compact size.

An internal view of how a catadioptric telescope works. Image credit SkyGazette.com

Types of catadioptric telescopes

Catadioptric telescopes come in a variety of designs, each suited to specific uses and preferences:

Schmidt-Cassegrain Telescope (SCT)

SCT's feature a spherical primary mirror and a thin corrector plate at the front to reduce spherical aberration. They are best for general-purpose observing and imaging, including planetary and deep-sky targets.

Maksutov-Cassegrain Telescopes

Maksutov-Cassegrains use a spherical primary mirror and a thick meniscus lens as the corrector, producing sharp, high-contrast images. It’s ideal for lunar and planetary viewing, thanks to its excellent optical quality and long focal length.

Schmidt-Newtonian Telescope

Schmidt-Newtonians combine the wide field of a Newtonian reflector with a Schmidt corrector plate to reduce coma (edge distortion). It’s great for astrophotography and visual observation.

Corrected Dall-Kirkham (CDK)

CDKs are like the Ritchey-Chrétien telescopes but they incorporate corrective lenses to flatten the imaging field. It’s ideal for advanced astrophotography because of its highly corrected field and sharp stars across the frame.

What are Catadioptric Telescopes Best Used For?

Catadioptric telescopes shine in a wide range of applications, making them ideal for both beginners and seasoned astronomers. Planetary observation stands out as the long focal lengths of Maksutov-Cassegrains (Maksutovs) and Schmidt-Cassegrains (SCTs) deliver crisp, detailed views of planets, revealing features like rings, moons, and surface textures. In astrophotography, their sharp optics and flat imaging fields capture stunning images of everything from planets to deep-sky objects like galaxies and nebulae.

SCTs strike a perfect balance between portability and performance, excelling in deep-sky observation, lunar viewing, and solar observation with the right filters. Their versatility suits both visual astronomy and astrophotography, making them a top choice for enthusiasts. However, their high price tag can put them out of reach for those on a limited budget. Although they’re great for high-magnification views, their narrow field of view restricts their use in wide-field deep-sky observation.

Pros and Cons of Catadioptric Telescopes

Pros

• Compact Design: Folded optical paths make them portable and easy to store.

• Versatility: Suitable for planetary, lunar, and deep-sky observing.

• Sharp Optics: Corrector plates and lenses ensure minimal aberrations.

• Ease of Use: Many come with motorised mounts and GoTo systems.

Cons

• Price: Typically more expensive than standard reflectors or refractors.

• Cool-Down Time: Enclosed tubes and lenses take longer to reach thermal equilibrium.

• Field of View: Narrower compared to Newtonians of similar aperture.

Which Brands Are Highly Recommended

There are some great catadioptric telescope models to suit all budgets and skill levels. The Celestron NexStar 6SE (SCT), with a 150mm aperture, features a computerized GoTo mount, a compact design, and excellent optics, making it ideal for beginners to intermediates looking for a versatile telescope for planetary and deep-sky viewing. The Sky-Watcher SkyMax 127 (Maksutov), with a 127mm aperture, offers high-contrast optics and a portable design, perfect for planetary and lunar enthusiasts.

Smart Telescopes

Smart telescopes combine cameras, automated tracking, and advanced image processing in a sleek, all-in-one design. They make stargazing as simple as tapping a screen.

They use built-in sensors and software to align themselves and track celestial objects automatically. Instead of using an eyepiece, you view enhanced, live-stacked images directly on your smartphone or tablet, creating a seamless and intuitive experience.

Smart telescopes are ideal for beginners and casual users who want quick, stunning results without the hassle of manual adjustments. Advanced astronomers, however, may find their limited customisation options restrictive.

What Are Smart Telescopes Best Used For?

Smart telescopes shine in light-polluted areas, where their image-stacking software enhances faint details. They’re perfect for:

• casual astrophotography.

• sharing celestial views with family and friends.

• exploring the night sky with minimal setup and effort.

Pros and Cons of Smart Telescopes

Pros

• User-Friendly: Fully automated alignment and tracking.

• Portable: Compact and lightweight designs.

• Impressive Imaging: Live-stacked, enhanced visuals perfect for light-polluted areas.

• Sharing Made Easy: View and share images directly via smartphones or tablets.

Cons

• High Cost: Some premium models have premium price tags.

• Limited Control: They lack customisation for advanced uses, such as shooting with narrow broadband filters.

• Battery Reliant: Dependent on software and power for operation.

Which Brands Are Highly Recommended

The Vaonis Stellina is a sleek, portable telescope with high-end imaging capabilities, making it perfect for urban skies where light pollution can be an issue. The Unistellar eVscope 2 offers excellent light amplification, providing a more immersive experience that’s great for beginners and casual users who want to explore the night sky with ease.

The DWARF II Smart Telescope is a compact, budget-friendly option for entry-level astrophotography, offering an affordable way to start capturing celestial wonders. The SeeStar S30 stands out with its user-friendly design and advanced features, providing a solid choice for both beginners and enthusiasts looking for a versatile, easy-to-use telescope for stargazing and imaging.

Common Telescope Mistakes to Avoid

When you’re first getting into stargazing, it’s easy to get excited and make a few rookie mistakes. But don’t worry, we’ve all been there! Here are some common telescope blunders beginners often make—and how to avoid them:

1. Focusing Too Much on Magnification: It’s tempting to think that more magnification means better views, but that’s not the case. High magnification can make your images blurry, shaky, and hard to focus on, especially in less-than-ideal seeing conditions. The key to great views is a balance between the aperture (the size of the lens or mirror) and magnification. More light means more detail, so prioritize a telescope with a larger aperture for clearer images.

2. Overlooking the Importance of Aperture: Many beginners get drawn to a telescope based on its price or its flashy features, but aperture is king when it comes to seeing detail. A larger aperture allows the telescope to collect more light, which is essential for sharp, detailed views of distant objects like galaxies, nebulae, and faint stars. So, before you buy, make sure to check the aperture size—it can make all the difference in your stargazing experience.

3. Choosing a Telescope That’s Too Complex: If you’re just starting, don’t go for the most advanced telescope on the market. Sure, it might have all the bells and whistles, but if you don’t understand the basics of how telescopes work, it could be more frustrating than fun. Start with something simple—like an entry-level refractor or a small reflector—that’s easy to set up and use. You can always upgrade once you get the hang of it.

4. Ignoring the Mount: A telescope mount is just as important as the telescope itself. If you end up with a cheap, unstable mount, you’ll be dealing with wobbly views and frustration. An unstable mount makes it harder to track objects, especially if you're trying to do astrophotography. Look for sturdy mounts that suit your telescope type—whether it’s an Alt-Azimuth mount (easy to move up and down, left and right) or an Equatorial mount (for tracking celestial objects across the sky).

5. Neglecting Regular Maintenance: Telescopes need a little TLC to keep performing at their best. Neglecting things like cleaning the lenses, checking for dust or moisture, and ensuring the optical components are properly aligned (collimated) can lead to blurry or dim views. Be sure to regularly maintain your telescope to keep it in top shape and ready for those starry nights!

Avoiding these mistakes will not only save you time and money, but it will also make your astro-journey more enjoyable. With the right telescope and a little know-how, you’ll be well on your way to exploring the cosmos!

Telescope TLC: How to Keep Your Lenses and Mirrors Sparkling

Alright, so you’ve got your shiny new telescope, but just like anything else, it needs a bit of TLC. Telescope maintenance isn’t as scary as it sounds — it’s mostly about keeping things clean and in good shape. A quick wipe-down of the lenses, checking for dust or debris, and making sure all the moving parts are running smoothly can make a big difference. After all, you don’t want to be staring at blurry stars just because you forgot to give your telescope a little love!

Cleaning your telescope’s lens or mirror is pretty straightforward, but it does require some care. Start with the lens by gently blowing off any loose dust or debris using a can of compressed air (definitely avoid puffing with your breath, as that can leave moisture behind). Then, use a soft, lint-free microfiber cloth to wipe the lens in a circular motion. If you’ve got some stubborn grime, dampen the cloth with a tiny bit of distilled water or a specialised lens-cleaning solution.

When it comes to the mirrors, things get a bit more delicate. Again, start with compressed air to get rid of dust. For a deeper clean, use a soft brush (think camel hair) to gently remove any residue. If dirt's being persistent, a very dilute solution of distilled water and isopropyl alcohol can do the trick. Just make sure not to apply too much pressure and steer clear of harsh cleaning products that could damage the coating! Always go for products made specifically for optics — your telescope will thank you!