Many amateur astronomers are surprised by the results they get when they upgrade their telescope's eyepiece. Things look so different, it's almost as if they had bought a whole new telescope! Deciding on the right style and quality of telescope eyepiece, though, takes some effort to get such a great change.
Sorting through the many eyepiece options out there can be as daunting as it was choosing your telescope in the first place. Fortunately, the options break down into logical categories. Once you understand those categories, selecting the right eyepiece is pretty straightforward.
For this comparison guide we considered a range of seven eyepieces and two eyepiece kits, chosen to represent a spectrum of prices and features that will appeal to any level of amateur astronomers (and maybe even a few pros.)
FAQs About Telescope Eyepieces
To provide you with a telescope eyepiece primer, we pulled from the questions amateur astronomers asked the most often when they seek to expand their eyepiece knowledge:
1. What Is A Telescope Eyepiece?
A telescope eyepiece magnifies and focuses the light initially collected by your telescope’s objective lens or mirror so your eye can see the image.
Essentially, an eyepiece is a small tube (typically 1.25 inches in diameter) containing one or more glass elements that refract the light and direct it to a small opening where you place your eye.
Most telescope eyepiece mounts are engineered to accommodate quick changes of eyepieces, so the viewer can switch up magnifications and other factors by changing the eyepiece.
2. What Does An Eyepiece Have To Do With A Telescope’s Magnification?
A telescope’s magnification power is determined by two factors:
Magnification = Objective focal length / Eyepiece focal length
This means that a telescope’s magnification level can be changed by changing the eyepiece. This has a very practical application. For example, when aligning a telescope to a specific celestial object, telescope users will often use lower magnification to see more of the sky so they can find the object first. Then, they change eyepieces to zoom in on the object.
A lower eyepiece focal length (FL) provides higher magnification. Though it sounds appealing, higher magnification is not always desirable. Higher magnification means a tradeoff in seeing a narrower section of the sky. Many celestial objects are too big to fit in a narrow field of view.
Additionally, magnification tends to exacerbate optical issues, such as telescope vibration and atmospheric distortions. Thus, you have to balance what you are trying to look at with the limitations of magnification. Sometimes less is more.
3. What Sizes Do Telescope Eyepiece Come In?
There are two “size” considerations when talking about eyepieces.
Focal Length (FL) — This is the distance between the point at which light enters the eyepiece barrel and where it is focused so your eye sees a clear image. Manufacturers typically etch a label listing FL on the side of an eyepiece for easy identification.
Barrel Size — This is the eyepiece’s diameter. It must fit the diameter of the “seat” (eyepiece mount) on the telescope. Our list includes both 1.25-inch and 2-inch barrel diameter telescope eyepieces.
4. What Is Eye Relief?
Eye relief describes how high above the lens your eye has to sit to see through it clearly. Longer eye relief is handy for those who wear glasses, as it provides space for the glasses. Eye relief becomes more important as an eyepiece's FL goes down.
5. What Is An Eyepiece’s Field Of View?
Eyepieces will be listed with an Apparent Field of View (AFOV). This is the circle of sky visible through the eyepiece, and it is expressed in degrees of the arc of sky.
However, the Total Field of View (TFOV) that you see through the eyepiece is actually limited by the magnification created by the combination of the telescope and the eyepiece. Thus, we have to make a calculation to determine the TFOV you actually see through that eyepiece on your telescope.
TFOV = AFOV / Magnification
How We Reviewed
To select eyepieces for our list, we surveyed the top-rated items from expert online astronomy sites. We sought a spectrum of eyepieces that would be representative of the best available for different levels of amateur astronomers. Then, we considered their individual features, pros and cons, prices, warranties and even some user reviews.
Overall Price Range Of Telescope Eyepieces
Even though our list of eyepieces range in price from $20 to $630, they are all valuable, list-worthy pieces. To gather a spectrum of eyepieces to suit every budget, we had to consider high-quality, entry-level units, as well as higher-end eyepieces with additional engineering and features.
What We Reviewed
Eyepieces Celestron 93230 Zoom Eyepiece
- Zoom from low to high power in an instant with this versatile eyepiece!
- Compatible with any telescope that accepts 1.25" eyepieces
- This fully multi-coated Premium eyepiece zooms to any focal length between 8 mm and 24 mm - pick the best magnification...
This telescope eyepiece allows you to “zoom” from a 24mm focal length to an 8mm focal length simply by twisting its barrel. This saves you the step of having to switch to another eyepiece.
This Celestron eyepiece has a wide 40- to 60-degree AFOV, which is perfect for viewing larger celestial objects, such as the moon and planets. Fully-coated multicolor optics help reduce reflections and optical color distortions. It also has 15mm to 180mm eye relief, providing wearers of glasses enough room to see through the lens without cramming their lenses into their faces.
This eyepiece is protected with a 2-year manufacturer’s warranty on materials and workmanship.
Tele Vue 13mm Ethos Eyepiece
This high-end, yet still amateur-accessible telescope eyepiece has a remarkable 100-degree AFOV. It has a 13mm FL, which places it in the middle, as far as magnification goes. Its 15mm eye relief means it has room for your glasses. It also accepts DIOPTRX eyesight astigmatism correctors. Though we kept to 1.25-inch eyepiece barrels, this eyepiece can also fit 2-inch telescope eyepiece seats.
This eyepiece is covered by a 5-year warranty on materials and workmanship. (But be sure to save the receipt packaging.)
Orion LHD Lanthanum Ultra-Wide Eyepiece
- With fully multi-coated 8-element optics, the 20mm focal length telescope eyepiece will amaze you with true-color views...
- Orion LHD eyepieces feature high-index, low-dispersion lanthanum glass to eliminate chromatic aberrations for...
- All Orion LHD telescope eyepieces boast an ultra-wide 80-degree apparent field of view for an immersive viewing...
The Orion’s ultra-wide 80-degree AFOV makes it great for viewing wider celestial bodies, while its 20mm focal length brings brightness and color to your line of sight. The eyepiece’s specialized lanthanum glass helps eliminate chromatic distortion for crystal-clear images. It also has 20mm eye relief and a wide 30mm lens, making this an exceptional choice for those wearing eyeglasses. Barrel width is 2 inches.
Orion backs this eyepiece with a 1-year manufacturer’s warranty on materials and workmanship.
Baader Planetarium Mark IV Eyepiece
This telescope eyepiece aims for versatile adaptability. Not only does it zoom to multiple focal lengths (24, 20, 16, 12 and 8), it comes with an adapter to fit either 1.25-inch or 2-inch barrel seats. Though zoom-style eyepieces trade some optical quality for their convenience, the reviews are all positive from consumers who have used this one.
This eyepiece is protected by a 2-year manufacturer’s warranty for materials and workmanship.
Celestron X-Cel LX Series Eyepiece
- X-Cel LX eyepieces, optimized for planetary viewing, offer a 60° field of view through a six-element fully multi-coated...
- Pop-up rubber eyeguards provide comfort and increase contrast. Raise and lower with a simple twist.
- A treaded rubber grip offers a no-slip grip, even with gloves on
This is a 1.24-inch barrel, 2.3mm focal length telescope eyepiece. This line of Celestron eyepieces, with wide AFOVs (60 degrees here) is designed for viewing planets. Six multi-coated lens elements present a clear, bright image for brighter objects. Barrel is threaded for attaching filters.
The materials and workmanship of this eyepiece is covered by a 2-year manufacturer’s warranty.
Tele Vue Nagler Apparent Field Eyepiece
This is a 1.25-inch barrel, 3.5mm focal length telescope eyepiece with an AFOV of 82 degrees. The wide AFOV lends itself to planetary viewing, and its 12mm eye relief is excellent at accommodating those who wear glasses.
Amazingly, this eyepiece is covered by a limited lifetime warranty.
Gosky Plossl Telescope Eyepiece
No products found.
This 1.25-inch barrel, 8mm focal length telescope eyepiece has a 52-degree AFOV, which gives it a balance between magnification and field of view. This makes it great for moon viewing, as well as for gazing at mid-sized star clusters and nebulas. Plossl uses a classic four-lens element design to maximize optical clarity and eye relief.
This eyepiece also is covered by a limited lifetime warranty.
Eyepiece Kits Celestron 14-Piece Eyepiece And Filter Kit
- Five superior grade Plossl eyepieces, all fully multi-coated for maximum contrast and resolution
- 2x, 1.25-inch Barlow lens gives you a total of ten power combinations
- Six colored eyepiece (planetary) filters.A tight fit is better, so remove the least amount of foam possible before...
In contrast to the first part of our list, this eyepiece kit, complete with case and accessories, provides you with a spectrum of focal lengths for an amateur astronomer interested in investing in options and versatility.
Included are five 1.25-inch barrel Plossl telescope eyepieces (focal lengths: 32mm, 17mm, 13 mm, 8mm, and 5mm) and a “Barlow” adapter, which doubles the focal length of any one eyepiece. So, essentially, this eyepiece kit gives you 10 eyepieces.
Each eyepiece has a 52-degree AFOV. Also included is a collection of filters that adjust your color view to bring out the details of specific planets and the moon. All this kit's great pieces are contained in one aluminum, foam-lined carrying case.
This kit is covered by a 2-year manufacturer’s warranty on materials and workmanship.
Gosky Premium Eyepiece Set
- This fifteen-piece 1.25 inch astronomy accessory kit let you get the most out and enhances the performance of your...
- 6mm/8mm/12.5mm/ 20mm/40mm Multi-Coated plossl eyepiece--for different power planetary and lunar observation broad-field...
- 5 color planetary filters -- The five color filters (Red, Blue, Orange, Green＆Yellow) and a polarizing filter...
This eyepiece kit features five different Plossl eyepieces (focal lengths: 40mm, 20mm, 12.5mm, 8mm and 6mm) and a Barlow adapter that doubles each eyepiece’s focal length. Essentially, that is another 10 eyepieces in a single kit.
Additionally, this kit comes with six colored filters and a moon filter for bringing out the specific colors and contrasts of the planets. The eyepieces and adapter have 1.25-inch barrels and 52-degree AFOV. Plus, everything is stored in an aluminum, foam-lined carrying case.
This kit's materials and craftmanship are covered by a 1-year manufacturer's warranty.
With such a spectrum of options on our list, it is difficult to pick a single favorite. With that said, we feel that the eyepiece kits provide the novice astronomer with an affordable means to experiment with filters and with various eyepieces of differing focal lengths.
On the other hand, zoom eyepieces like the Celestron 93230 put much of that same functionality into a single device, rather than contained in a kit. For the price, we feel it is a worthy investment for any astronomer looking to grow their existing telescope setup.
Much of being an amateur astronomer is experimenting to learn what works best for your particular sky-gazing goals. Any of the telescope eyepieces (or kits) on our list would further that endeavor.
Featured Image via Pexels