How to Choose the Right Telescope Accessories

Buying a telescope is only the beginning. The right accessories can expand what you can see, make your telescope easier and more comfortable to use, and help you get more out of every observing session.

But you don't need every accessory at once. Some will change the view through your telescope, while others solve practical problems like finding objects, preventing dew, powering a computerized mount, or protecting your equipment.

Here's a look at the most useful telescope accessories and how to decide which ones belong in your setup.

Eyepieces

Eyepieces are among the most important telescope accessories because they play a major role in determining your magnification and field of view. Most Celestron telescopes include at least one eyepiece to get you started, but adding different focal lengths gives you more options for observing different targets.

As a general rule:

  • Longer focal length eyepieces, such as 25mm to 40mm, provide lower magnification and wider fields of view. They're useful for locating objects and observing larger targets like star clusters and nebulae.
  • Shorter focal length eyepieces, such as 6mm to 10mm, provide higher magnification and narrower fields of view. They're better suited to closer looks at the Moon, planets, and double stars.

Eyepieces also come in different optical designs. Beyond focal length, an eyepiece’s design affects characteristics like how wide the view appears, how comfortably you can position your eye, and how sharp the image remains across the field. Each design offers different advantages depending on your telescope and observing preferences.

  • Kellner: A three-element design commonly found with entry-level telescopes. They provide bright, sharp views, particularly with slower focal-ratio telescopes like many refractors.
  • Plössl: A versatile four-element design that offers good sharpness and contrast for both planetary and deep-sky observing.
  • Erfle: Offers a wider apparent field of view, typically around 60°, creating a more expansive view that is well-suited to deep-sky observing.
  • Wide-Field Flat: Designed to provide a flatter field with improved clarity from the center toward the edge.
  • Zoom: Allows you to change magnification by adjusting the eyepiece's focal length rather than swapping eyepieces.
  • Ultra Wide Field: Provides an expansive apparent field of view, up to 82° or more, for a more immersive observing experience.

You don't need a drawer full of eyepieces to get started. A selection covering low, medium, and high magnification will handle a wide range of observing targets.

LEARN MORE: Take a deeper dive with Types of Telescope Eyepieces: From Kellner and Plössl to Modern Designs—an essential resource to keep in your astronomy kit. Also, check out our article How to Determine Which Eyepieces to Use with Your Telescope.

Eyepieces

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Barlow Lenses

A Barlow lens increases the magnification provided by an eyepiece, typically by 2x or 3x. It's an easy way to expand the range of magnifications available to you without purchasing several additional eyepieces.

For example, using a 25mm eyepiece with a 2x Barlow provides the same magnification as a 12.5mm eyepiece.

That makes a Barlow especially useful when you're building your first eyepiece collection. One Barlow can effectively provide several of your existing eyepieces with an additional magnification option.

LEARN MORE: What is a Barlow Lens?

Barlow Lens


Star Diagonals

A star diagonal redirects the light path by 90°, placing the eyepiece in a more comfortable viewing position. This can make a big difference, especially when your telescope is pointed high in the sky, reducing the need to strain your neck.

Star diagonals are commonly used with refractors and compound telescopes, including Schmidt-Cassegrains, Maksutov-Cassegrains, and EdgeHD telescopes.

Newtonian reflectors do not require a star diagonal because the optical design already directs the light to an eyepiece located on the side of the optical tube.

Diagonals


Telescope Filters

Filters can improve contrast, reduce brightness, or emphasize particular features depending on what you're observing.

  • Moon filters reduce the Moon's brightness for more comfortable viewing and can make subtle lunar features easier to see.
  • Color filters can increase contrast in certain planetary features, helping bring out details on targets like Mars, Jupiter, and Saturn.
  • Light pollution filters are designed to selectively block certain wavelengths of artificial light, improving contrast when observing from light-polluted locations.

Most telescope filters thread directly onto compatible eyepieces or Barlow lenses. Some can also be stacked, allowing you to combine their effects. However, we don’t recommend stacking filters unless your telescope is 8” in aperture or larger.

Visual and imaging filters serve different purposes, so be sure to choose a filter designed for the type of observing you're doing. We'll cover filters specifically designed for cameras in our Astroimaging Accessories Guide.

LEARN MORE: For a detailed breakdown of visual filter types and their uses, click here.


Finderscopes

Before you can observe an object through your telescope, you have to get the telescope pointed toward it. That's where a finderscope comes in.

A finderscope, or finder, is mounted on the telescope and provides an easier way to aim at celestial objects before viewing them through the main telescope. Many telescopes include one, but several styles are available.

  • Optical finderscopes provide a magnified view with a wider field than the main telescope.
  • Red-dot finders project a reference point that helps you aim the telescope toward a visible object or area of the sky.
  • Right-Angle Correct Image (RACI) finderscopes provide a magnified, correctly oriented view while allowing you to look through the finder from a more comfortable angle.

The best choice depends on your telescope, the objects you observe, and your personal preference.

LEARN MORE: Finderscopes 101: How to Choose and Care for Your Telescope's Key Tool


Maps and Observing Aids

Not every useful telescope accessory attaches to the telescope.

Star charts, Moon maps, observing guides, apps, and planetarium software can help you identify objects, decide what to observe, and plan a night under the stars.

Celestron offers several options:

  • Celestron Sky Maps: Star charts showing constellations, stars, and other celestial landmarks.
  • Observer’s Map of the Moon: A detailed lunar poster identifying prominent craters, maria, landing sites, and other features.
  • Celestial Calendar: Every year, Celestron experts create a free guide to notable upcoming astronomical events, including eclipses, conjunctions, and meteor showers.
  • Planet and Constellation Guides: Free reference materials from the Celestron team with observing information, target locations, and other useful details.
  • Starry Night Software: Included with many Celestron telescopes, this planetarium software lets you explore the sky and plan observing sessions from your PC.


Books

Apps and Telescope Control

Your smartphone can also be a useful observing tool. Celestron offers several astronomy apps—all powered by SkySafari™—with features ranging from interactive sky maps and observing information to telescope navigation and control.

  • SkyPortal Powered by SkySafari™: Use SkyPortal on its own to explore the night sky with an interactive planetarium, identify celestial objects, and learn more about what you’re observing. You can also use the app to control a compatible Celestron computerized telescope via WiFi. Some telescopes, like the NexStar Evolution, have built-in WiFi, or you can add wireless connectivity to many Celestron computerized telescopes with the SkyPortal WiFi Module. Once connected, you can select and slew to objects directly from your smartphone or tablet.
  • StarSense Explorer App Powered by SkySafari™: Works with StarSense Explorer telescopes to analyze the night sky and calculate the telescope’s position in real time. Follow the on-screen arrows to planets, stars, and galaxies with bullseye accuracy.
  • Celestron Origin App Powered by SkySafari™: Designed specifically for the Origin Intelligent Home Observatory, the app controls the complete observing experience, from selecting and locating targets to capturing and processing images.

In addition to using mobile apps, you can take control of a compatible Celestron computerized telescope from your Windows PC.  Celestron PWI Telescope Control Software (CPWI) includes an interactive planetarium interface for finding and slewing to objects, advanced alignment and mount modeling for improved pointing accuracy, and control of compatible accessories. Connect to your telescope by cable or, with compatible setups, over WiFi.


Automatic Alignment

Want to spend less time setting up and more time observing? StarSense AutoAlign V2 automatically aligns compatible Celestron computerized telescopes using advanced plate-solving technology. Once aligned, Precise GoTo improves pointing accuracy, placing objects near the center of your eyepiece.

StarSense AutoAlign V2 can also assist with polar alignment on compatible equatorial mounts and alt-azimuth mounts on a wedge, and offers USB-C connectivity for Live View, diagnostics, and firmware updates. You can control it with the NexStar+ hand control, SkyPortal Powered by SkySafari™, or Celestron's CPWI software for PC.


Dew Prevention

A perfectly clear night can end surprisingly quickly when condensation shows up on your telescope's optics. Dew forms when your telescope's optics cool below the surrounding air's dew point. Several accessories can help prevent that moisture from accumulating.

  • Dew shields extend beyond the front of the telescope to help protect exposed optics from moisture and stray light. Refractors typically incorporate a dew shield into the optical tube, while compound telescopes such as Schmidt-Cassegrains and Maksutov-Cassegrains can benefit from an add-on shield.
  • Dew heaters and heater rings provide gentle heat to help keep optics above the dew point.
  • For more automated control, Celestron's Smart DewHeater Controllers regulate compatible heating accessories to manage heat and power consumption during an observing session.

The right solution depends on your telescope and observing conditions. Particularly damp environments may call for a combination of dew-prevention accessories.

Dew Prevention

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Solar Filters

SOLAR WARNING: Never look at the Sun through a telescope without a proper solar filter designed for your equipment.

Solar observing requires dedicated filtration to reduce the Sun's intense visible, ultraviolet, and infrared radiation to safe levels.

Celestron's EclipSmart line is designed for direct observation of the Sun, sunspots, and solar eclipses. EclipSmart products use Solar Safe filter technology and conform to the ISO 12312-2:2015(E) international safety standard.

Before observing the Sun, always make sure you're using the appropriate solar filter for your telescope and follow all instructions supplied with the product.

EclipSmart Solar Safe Products


Portable Power

If you use a computerized telescope, powered mount, dew-prevention equipment, or other electronic accessories, a reliable power source becomes an important part of your observing setup.

A portable power supply lets you operate your equipment off-grid, whether you're observing in the backyard or traveling to a dark-sky location.

Celestron PowerTank portable batteries are designed to provide power for compatible telescope mounts and accessories, with options for different equipment and observing needs.

Powertank


Telescope and Accessory Storage

The right storage can help protect your telescope and accessories at home and make them easier to transport to your observing site. The best option depends on what you’re storing and how often you travel with your gear.

  • Padded telescope bags offer lightweight protection and are easy to carry, making them a convenient option for transporting optical tubes, tripods, and other equipment.
  • Hard-shell cases provide more substantial protection for delicate or higher-value equipment. Larger roller cases add wheels and handles, making heavier telescopes and mounts easier to move.
  • Accessory cases keep smaller items like eyepieces, filters, adapters, and cables organized and protected, so everything is easy to find when you set up.
  • Telescope covers are useful when your telescope will remain assembled between observing sessions, helping shield it from dust and other environmental exposure without requiring you to pack everything away.


Cases & Bags

Which Telescope Accessories Do You Need First?

You don't need to buy everything on this list before your first observing session. Start with the accessories included with your telescope, then add equipment based on what you'd like to improve.

Want more magnification options? Start with an additional eyepiece or Barlow lens. Having trouble locating objects? Consider a different finder or observing aid. Fighting condensation? Look at dew prevention. Taking your telescope on the road? Storage and portable power may move higher on your list.

The goal isn't to collect accessories. It's to build a setup that works better for where, when, what, and how you like to observe.

And if you're ready to start capturing the night sky with a camera, continue with our Astroimaging Accessories Guide. Still shopping for your first telescope and not sure where to begin? Check out our How to Buy Your First Telescope guide to help you find the right telescope for your needs.

Frequently Asked Questions for First-Time Telescope Buyers

What telescope should I get?

The best telescope is the one you’ll actually use every clear night! Select a model that suits your budget, aligns with your desired observing targets, and accommodates your setup preferences (manual or computerized). A telescope that’s easy to transport and quick to set up will get used far more often than one that’s bulky or complex. Check out our recommendations above for our top picks.

Which telescope is best for planets, the Moon, or deep-sky objects?

Different telescope designs excel for different targets. For bright Solar System objects, such as the Moon and planets, opt for a telescope with a longer focal length for higher magnification and finer detail. Refractors, Maksutov-Cassegrains, and Schmidt-Cassegrains are excellent options. For deep-sky objects like galaxies, nebulae, and star clusters, a larger aperture helps reveal faint details; Newtonian reflectors and SCTs excel here. If you want to explore both, SCTs offer the best balance and versatility. The key is to match the telescope’s strengths to the celestial sights that excite you most. Read more

Does telescope aperture size matter?

Yes. Aperture determines how much light your telescope gathers. The larger the aperture (the diameter of the primary lens or mirror), the brighter and sharper your views will be. A larger aperture reveals fainter objects and finer details. However, bigger isn’t always better—larger telescopes are heavier and take longer to set up. The best choice is one you can manage comfortably and will use often. Read more

What do focal length and focal ratio mean?

Focal length is the distance light travels inside your telescope before reaching focus, and it determines magnification and field of view. A longer focal length offers higher magnification and narrower views, which is perfect for studying planets or the Moon. A shorter focal length gives a wider view, ideal for sweeping across star fields or viewing large nebulae.

The focal ratio (f/number) is the relationship between focal length and aperture. Telescopes with a fast focal ratio (f/2–f/6) produce brighter, wide-field images, making them excellent for deep-sky observing and astrophotography. Slower focal ratios (f/8–f/10) are better suited for high magnification and planetary detail.

What do the numbers on eyepieces mean, and how do they affect my view?

An eyepiece’s number, such as 10mm or 25mm, represents its focal length. Smaller numbers provide higher magnification and a narrower field of view, revealing finer details in planets or the Moon. Larger numbers offer lower magnification and a wider field of view, which is ideal for locating objects and observing large star clusters or nebulae. Start each session with a low-power eyepiece to locate your target, then switch to a higher-power eyepiece for close-up details.

How do I choose eyepieces that work best with my telescope?

Every Celestron telescope lists a minimum and maximum useful magnification. Staying within this range ensures your views remain sharp and bright. A good eyepiece collection includes three focal lengths: one for low power and wide views, one for medium power, and one for high magnification. To expand your range affordably, consider a Barlow lens, which multiplies the magnification of your existing eyepieces. Read more

What size telescope should I buy?

Choose the largest aperture you can comfortably handle, store, and afford. Larger telescopes reveal fainter objects and more detail, but portability is also important—if it’s too heavy or complicated to move, it may stay in storage. For most beginners, a small to mid-size telescope, such as a 102mm refractor or 130mm reflector, strikes the right balance of performance and ease of use.

Should I get a manual or computerized telescope?

Manual telescopes are budget-friendly and great for learning the night sky through star-hopping. You’ll find and track objects yourself, which builds valuable observing skills. Computerized, or GoTo, telescopes locate and follow celestial objects automatically. They’re ideal for convenience, precision, and astrophotography, although they require power and some setup. Your choice comes down to how much guidance you want from your telescope.

Should I use an alt-azimuth or German equatorial mount?

Alt-az mounts move up and down, left and right, much like a camera tripod. They’re intuitive and perfect for beginners who want simple operation. Equatorial mounts are designed to track celestial objects as Earth rotates, making them essential for long observing sessions and astrophotography. If you’re just starting out, an alt-az mount offers simplicity; if you plan to image or track for long periods, an EQ mount is worth the investment. Read more

What accessories will I need for my first telescope?

To get the most out of your telescope, add a few key accessories. A selection of eyepieces with varying focal lengths provides flexibility in magnification. A Barlow lens doubles or triples the power of your eyepieces, expanding your viewing options. Filters enhance contrast and reveal hidden details, while a portable power source, such as a PowerTank, ensures your telescope runs smoothly all night. As you grow, consider a padded case to keep your gear protected.

What’s the purpose of a finderscope?

A finderscope, or red-dot finder, helps you aim your telescope. It provides a much wider view of the sky, allowing you to align on bright stars or planets before looking through the main telescope. Once your target is centered in the finderscope, it will appear in your eyepiece, making setup and object location much easier. Read more

Can I take pictures through my telescope?

Yes! You can start simply with a smartphone adapter to capture bright objects, such as the Moon and planets. If you already own a DSLR, use a T-ring and T-adapter to attach it to your telescope for more advanced imaging. For those seeking the best performance, dedicated astronomy cameras are designed for long-exposure imaging and capturing faint, deep-sky targets. Some systems, like Celestron Origin, even stack and process images automatically. Read more

Can I use my telescope during the day?

Yes, but only with the proper setup. For daytime observing, you can use your telescope to view distant landscapes or wildlife. For solar observing, always use a certified solar filter that meets ISO 12312-2:2015(E) standards. Never look at the Sun through a telescope without proper filtration—it can cause instant, permanent eye damage. For how to view land objects with a telescope, click here, and for more information on solar observing, click here.

What can I realistically expect to see with my telescope?

With a beginner or entry-level telescope, you can expect to see craters, ridges, and shadows on the Moon in stunning detail. Saturn’s rings and Jupiter’s cloud bands and moons are easily visible, and you may catch glimpses of Mars’s polar caps when it’s close to Earth. Venus shows distinct phases, and Mercury can be spotted before sunrise or after sunset. Bright star clusters, such as the Pleiades, and nebulae, like Orion, will appear as soft, glowing clouds, while galaxies, like Andromeda, will look like faint smudges of light. You won’t see the vivid colors captured in long-exposure photos, but viewing these objects in real time with your own eyes is an awe-inspiring experience that never gets old.

What are astronomy binoculars, and how do they compare to telescopes?

Astronomy binoculars are a simple and portable way to start exploring the night sky. They offer wide views that make it easy to find objects like the Moon, star clusters, and bright nebulae. While they can’t match a telescope’s magnification, they’re lightweight, quick to set up, and perfect for beginners who want a casual introduction to stargazing.

How does light pollution affect my viewing experience?

Light pollution brightens the night sky, washing out faint objects like galaxies and nebulae. To improve contrast, consider using a light pollution filter, which selectively blocks certain wavelengths of artificial light. If possible, travel to a dark-sky location, away from city lights, for optimal observing conditions. Read more

Are there astronomy apps and software that can help me?

Absolutely. Celestron’s suite of mobile apps, powered by SkySafari™, helps you explore the night sky with ease. Paired with their respective telescopes, SkyPortal offers guided tours and telescope control, StarSense Explorer uses your phone’s camera to guide you to targets, and the Celestron Origin app automates smart imaging. For desktop users, Starry Night software provides advanced tools for planning observing sessions. It’s included with every Celestron telescope purchase.

Do telescopes require power?

Manual telescopes operate without power, but computerized models need electricity to run their motors and tracking systems. Celestron’s PowerTank portable battery packs provide reliable 12V power to keep your telescope and accessories running through long observing sessions, whether at home or under dark skies.

How do I set up my telescope for the first time?

Begin on a stable, level surface. Assemble the mount, attach your telescope, and start with a low-power eyepiece to locate your first target. For equatorial mounts, align the polar axis toward Polaris. Every Celestron telescope comes with a Quick Setup Guide to walk you through these steps and help you get observing quickly.

How should I store my telescope, and can I leave it outside?

For best results, store your telescope in a cool, dry place, ideally in its original box, a padded bag, or a hard case to protect it from dust and damage. Always replace lens and mirror caps after observing, and avoid leaving your telescope in damp or dusty environments. Read more about telescope storage by clicking here.

We do not recommend keeping your telescope outside. Moisture, heat, and dust can damage optics and mechanical components. If you need short-term protection between sessions, use a weather-resistant cover, like Celestron’s telescope cover, to shield it from dew and light rain.

How much maintenance does a telescope need?

Most telescopes need very little maintenance. Refractors and Maksutov-Cassegrains are virtually maintenance-free, while reflectors may occasionally need collimation to realign their mirrors. Schmidt-Cassegrain, EdgeHD, and RASA systems maintain their alignment well but may require occasional collimation or readjustment over time. Always keep optics capped when not in use, and only clean lenses or mirrors when absolutely necessary, using proper tools.

Why does the view look upside down or reversed?

This is completely normal. Telescopes use mirrors and lenses that flip the image as light is focused. Since there’s no “up” or “down” in space, this orientation doesn’t affect astronomy. For terrestrial viewing, you can use an erect-image diagonal to correct the view. Read more

What is stellar magnitude, and how does it affect what I can see?

Stellar magnitude measures brightness. The lower the number, the brighter the object. The Sun shines at magnitude -26.7, while faint stars visible to the naked eye are around +6. Your telescope’s aperture determines how faint you can see—larger apertures reveal stars and galaxies invisible to the unaided eye. Read more

How long does it take to get comfortable using a telescope?

With a bit of practice, most beginners feel confident after a few sessions. Start with bright, easy targets like the Moon or Jupiter, and take your time learning to align, focus, and track. Every night under the stars builds experience, and soon the setup will feel second nature.

Can I see the International Space Station or the flags on the Moon with a telescope?

You can spot the International Space Station (ISS) as a bright, fast-moving point of light crossing the sky. With careful timing and tracking, larger telescopes may reveal its shape or solar panels, but not fine details. Click here to read more about observing the ISS.

The flags and landers left by Apollo missions are far too small to be seen from Earth, even with the most powerful professional observatories. Read our article about the flags on the Moon here.