So, you’re thinking about buying a telescope. That’s exciting! Knowing what to look for when buying a telescope is the most important step to ensure your first view of the rings of Saturn or the craters on the Moon is a memorable one. This guide will walk you through everything, from technical specs to practical tips, in simple language.
It’s easy to feel overwhelmed by choices and jargon. But don’t worry. We’ll break it all down. By the end, you’ll know exactly how to pick the right instrument for your eyes, your budget, and your night sky.
What To Look For When Buying A Telescope
This heading sums up your entire mission. The key factors you’ll need to consider all fall under a few main categories. Getting these right means you’ll spend more time stargazing and less time struggling with a frustrating piece of equipment.
The Three Main Types of Telescopes
Every telescope falls into one of three optical designs. Each has its strengths and weaknesses. Your choice here will shape your entire experience.
Refractor Telescopes
These use lenses to bend light to a focus. They look like a long, straight tube.
- Pros: Low maintenance (sealed tube), sharp, high-contrast images, excellent for the Moon, planets, and double stars. They are generally simple to use.
- Cons: Can become very large and expensive for a given aperture. Lower-cost models may show color fringes (chromatic aberration) around bright objects.
- Best for: Beginners who want a plug-and-play experience, lunar and planetary observers, and those in urban areas.
Reflector Telescopes (Newtonians)
These use a curved primary mirror to gather and focus light. The eyepiece is on the side of the tube near the top.
- Pros: Most aperture for your money. Excellent for viewing faint galaxies, nebulae, and star clusters. No color fringes.
- Cons: Require occasional collimation (mirror alignment). The open tube can let in dust. Bulkier than some designs.
- Best for: Deep-sky observers wanting large aperture on a budget, and hands-on beginners.
Compound Telescopes (Catadioptrics)
These use a combination of mirrors and lenses folded into a compact tube. Schmidt-Cassegrain (SCT) and Maksutov-Cassegrain (Mak) are the most common types.
- Pros: Very portable for their aperture. Versatile for both planets and deep space. Often sold with advanced mounts and electronics.
- Cons: Usually the most expensive design per inch of aperture. Can have longer cooldown times to reach night air temperature.
- Best for: Astrophotographers, observers who need portability, and those wanting a versatile, all-in-one system.
The Most Important Spec: Aperture
Aperture is the diameter of the telescope’s main light-gathering lens or mirror. It’s measured in inches or millimeters.
- Why it matters: A larger aperture collects more light. This means you can see fainter objects and achieve higher, clearer magnifications. It is the single most important factor in a telescope’s capability.
- The beginner’s rule: Get the largest aperture you can realistically afford, store, and carry. A good starting point is a 70mm (2.8″) refractor or a 114mm (4.5″) to 150mm (6″) reflector.
- Warning: Beware of department store telescopes that boast huge “power” but have tiny, shaky apertures. They will disappoint.
Understanding Magnification and Focal Length
Magnification is often overemphasized. It’s calculated by dividing the telescope’s focal length by the eyepiece’s focal length.
- Focal Length: The distance light travels inside the scope to reach focus. A longer focal length (e.g., f/10) is better for planets. A shorter one (e.g., f/5) is better for wide-field deep-sky views.
- Useful Magnification: A telescope’s maximum useful magnification is roughly 50 times its aperture in inches (or 2 times in mm). Pushing beyond this gives a dim, fuzzy image.
- Key Point: You change magnification by switching eyepieces. A good scope will come with one or two decent eyepieces. Plan to buy additional ones separately.
The Mount is Half the Telescope
A fantastic optic on a poor mount is useless. The mount holds the telescope steady and allows you to point it smoothly. There are two main types.
Alt-Azimuth Mount
This moves up-down (altitude) and left-right (azimuth). It’s like a camera tripod.
- Pros: Intuitive, simple to use, lightweight, and generally less expensive.
- Cons: Does not naturally follow the rotation of the night sky, which can be a issue for high magnification viewing or photography.
Equatorial Mount
This is aligned with Earth’s axis. It moves in right ascension and declination.
- Pros: Once aligned, you can follow celestial objects smoothly with just one knob. Essential for serious astrophotography.
- Cons: Heavier, more complex to set up, and more expensive.
Stability Test: Gently tap the tube of a mounted telescope. The image should settle within 2-3 seconds. If it shakes for longer, the mount is too weak.
Go-To vs. Manual Telescopes
Many telescopes now come with computerized “Go-To” mounts.
- Go-To: You align the system, then select an object from a database. The telescope slews to it automatically. Great for finding faint objects under light-polluted skies.
- Manual: You find objects by star-hopping using maps or apps. It’s more rewarding for learning the sky and costs significantly less for the same aperture.
- Consideration: Go-To systems add cost, weight, and require power. A manual scope puts more money into the optics itself.
Essential Accessories to Consider
The right accessories make a huge difference. Here’s what to look for.
- Eyepieces: Plossl eyepieces are a good standard start. Focal lengths like 25mm (low power) and 10mm (medium power) are versatile. Wider-field eyepieces (e.g., 68-degree) offer more immersive views.
- Finderscope: A small, low-power scope or red-dot finder mounted on the tube. It’s essential for aiming your telescope. A red-dot finder is often easier for beginners than a traditional optical finderscope.
- Barlow Lens: This doubles or triples the magnification of your eyepieces. A 2x Barlow effectively gives you two eyepieces for the price of one.
- Filters: A Moon filter cuts glare for more comfortable lunar viewing. A light-pollution filter can help in urban areas, but it’s no substitute for dark skies.
Setting Realistic Expectations
What you see will not look like Hubble photos. Those are long-exposure images.
Through an eyepiece, galaxies and nebulae will appear as faint, grayish smudges of light. Their beauty comes from knowing what you’re looking at—the light from millions of stars arriving at your eye. Planets, however, can show stunning detail: the cloud belts of Jupiter, the rings of Saturn, and the polar ice caps of Mars.
Your local viewing conditions are crucial. A small telescope under dark, rural skies will often outperform a large one in a bright city.
A Step-by-Step Buying Checklist
- Set Your Budget: Include money for a few key accessories (a better eyepiece, a planisphere, a book).
- Prioritize Aperture & Mount: Choose the largest stable setup you can manage.
- Choose Your Type: Reflector for deep-sky value, Refractor for lunar/planetary ease, Compound for portability and versatility.
- Manual or Go-To? Decide if you want to learn the sky or have the computer find it for you.
- Research Specific Models: Read reviews from astronomy forums and reputable magazines, not just retail sites.
- Buy from a Specialty Retailer: Avoid toy stores or general retailers. Shop with astronomy-focused dealers who offer support and quality products.
- Consider a Used Telescope: The astronomy community is great. A well-cared-for used scope can offer tremendous value.
Common Mistakes to Avoid
- Chasing Magnification: Ignore any box that says “500x power!” Useful magnification is limited by aperture and atmosphere.
- Choosing a Poor Mount: A wobbly mount will ruin your experience. Stability is non-negotiable.
- Starting Too Big: A huge, complex telescope that’s a chore to set up will stay in the closet. A smaller one you use often is better.
- Forgetting About Portability: Consider where you will store it and how far you’ll carry it. The best telescope is the one you actually use.
- Neglecting Your Sky Conditions: Be honest about your local light pollution. A wide-field scope might be more enjoyable than a high-power one if you’re in the city.
Your First Night Out
Once you have your telescope, practice setting it up in daylight. Learn how the mount moves and how to insert eyepieces.
For your first night, target the Moon. It’s easy to find and breathtaking at any magnification. Next, try Jupiter or Saturn if they’re visible. Use your lowest power eyepiece (highest mm number) first to find and center the object, then switch to a higher power one.
Be patient. Allow your eyes to adapt to the dark for at least 20 minutes. Use a red flashlight to preserve your night vision when reading charts.
FAQ Section
What is the best telescope for a beginner?
A Dobsonian reflector (a Newtonian on a simple, stable alt-azimuth mount) is often the top recommendation. It offers the most aperture for the money, is simple to use, and requires minimal setup. A 6-inch or 8-inch Dob is a fantastic start.
How much should I spend on my first telescope?
A good quality beginner telescope typically starts around $300 to $500. You can find smaller ones for less, but investing in this range ensures a stable mount and decent optics that won’t frustrate you. Remember, binoculars for under $150 are also a superb way to start exploring the sky.
Can I see planets with a cheap telescope?
Yes, you can. Even a small 70mm refractor will show Jupiter’s moons, Saturn’s rings (as a distinct shape), and the phases of Venus. More aperture will reveal greater detail, like cloud bands on Jupiter or the Cassini Division in Saturn’s rings.
Is a computerized telescope worth it for a beginner?
It depends on your personality. If you’re impatient or have severe light pollution, Go-To can help you find objects quickly. However, it adds complexity and cost. Many seasoned astronomers recommend learning the sky manually first, as it’s a deeply satisfying skill.
What can I realistically expect to see?
You can see: craters on the Moon, Jupiter’s cloud bands and four largest moons, Saturn’s rings, the Orion Nebula, the Andromeda Galaxy (as a fuzzy patch), star clusters like the Pleiades, and double stars. Colors are subtle except in a few bright planetary nebulae.
Where is the best place to buy a telescope?
Specialized astronomy retailers (online or local) are the best choice. Their staff understand the products and can offer support. They also sell reputable brands that you won’t find in big-box stores, which often carry poorly made models.
Final Thoughts
Choosing your first telescope is a big step into a rewarding hobby. Focus on aperture and a solid mount above all else. Start simple, manage your expectations, and prepare to be patient. The universe isn’t going anywhere, and the joy of finding a distant galaxy with your own equipment is an experience like no other.
Remember, the astronomy community is famously friendly and helpful. Local astronomy clubs often host “star parties” where you can look through different telescopes before you buy. Take advantage of this resource. Clear skies!