Unbiased Celestron Skymaster Giant 15X70 Binoculars Review

The Celestron SkyMaster 15x70 Binoculars aren’t exactly the most well-crafted or well-inspected big binoculars out there, but they are quite cost-effective and fairly good performers.
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The Celestron SkyMaster 15×70 Binoculars (not to be confused with the more expensive SkyMaster Pro 15x70s) are a popular budget pair of binoculars sold by Celestron. Many people pick up these binoculars in lieu of a beginner telescope. Our Binoculars vs. Telescopes article goes into why this may or may not be the right choice for you, but regardless, the SkyMaster 15x70s do offer a lot of light-collecting power – roughly equivalent to that of a 4” telescope – for about the same price, though they used to be a lot cheaper and easier to justify compared to purchasing the latter. The SkyMaster 15x70s have design and quality control compromises that are to be expected of binoculars this size trying to achieve a low price point, but they are fairly decent and provide acceptable performance, though the possibility of getting a bad (i.e., severely miscollimated) pair is unusually high.

How It Stacks Up

Ranks #4 of 24 $100 Astronomy Binoculars





Celestron SkyMaster 15x70 Binoculars


What We Like

  • Great optics with large 70mm aperture
  • Fairly affordable
  • Can still be used handheld or with a cheap tripod/monopod

What We Don't Like

  • Heavy/bulky compared to 50-60mm options
  • Quality control issues such as miscollimation on arrival
  • Junk tripod adapter
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Despite their limitations, if you’ve already got a telescope or can’t afford one, the SkyMaster 15×70 binoculars are an absolutely valuable supplement to your astronomy gear, provided that you can obtain a functional unit and understand what you are getting into.

Skymaster 15x70 Binocular
Pic by Zane Landers


The Celestron SkyMaster 15x70s use 70mm (2.75”) f/4 achromatic objective lenses. Unsurprisingly, these produce a lot of chromatic aberration, but at 15x magnification, you’d be hard-pressed to notice any on all but the brightest targets.

The Porro prisms employed in the SkyMaster 15x70s, as well as with most other good-quality binoculars, are made from BaK-4 crown glass. This surpasses the quality of the more prevalent BK7 prisms found in less expensive or inferior products. BaK-4 prisms are generally crafted to a higher standard than cheap BK7 ones, and binoculars utilizing these prisms typically do not have undersized prisms that could cause clipping or vignetting of the field of view. The exit pupils are nearly perfect circles, and the aperture of these binoculars is a genuine 70mm and has not been stopped down internally by a significant amount, with only the slightest clipping around one edge of the exit pupil, not enough to affect views.

For individuals who wear eyeglasses, these binoculars provide ample 18mm eye relief, enabling you to maintain a comfortable distance from your eyes while still experiencing the complete field of view. The true field of these binoculars is 4.4 degrees, which is approximately 9 times the angular diameter of the full Moon. With 15x magnification, this equates to an apparent field of view of 60 degrees, which is quite respectable and fairly immersive. However, the simplistic wide-angle design of the eyepieces combined with the fast f/ratio of the objective lenses inevitably results in some loss of sharpness toward the edges of the field of view. The outer 10-15% of the field is a little fuzzy, but you will probably not notice.

In terms of light-gathering capability, a pair of 70mm binoculars like these are roughly equivalent to a 4-inch telescope. However, unlike a telescope, they cannot provide high-power views of globular clusters, diminutive galaxies, the moon, or planets. Binoculars of this type are primarily suited for observing open clusters and expansive nebulae. There is a decent amount of chromatic aberration with the SkyMaster 15x70s on bright stars, the moon, and the planets, but it doesn’t hamper views in the slightest. 

Occasionally, the SkyMaster 15x70s, like many budget binoculars, may arrive miscollimated, resulting in a double image when looking through them. This is common enough to be a serious complaint of ours. Fortunately, Celestron’s customer service is usually able to resolve this issue, or you can access the adjustment screws yourself, though this may prove challenging. Either is time-consuming and can be significantly frustrating, however.


The fold-down eyecups of the Celestron SkyMaster 15x70s have a 50mm (2-inch) diameter. The interpupillary distance (IPD) of these binoculars can be adjusted between 56mm and 72mm. Focusing is accomplished using the central knob, while the right eyepiece features a diopter adjustment ranging from -4 to +8 to accommodate vision differences between your left and right eye.

In terms of durability, these binoculars boast a sturdy and well-built construction. While it is always advisable to avoid subjecting them to any kind of impact, they are likely to withstand accidental incidents. However, if they are dropped, collimation might be necessary, which could involve sending them back to Celestron—a potentially inconvenient process – or trying to do it yourself, which requires wrecking the rubber housing to access the tiny collimation screws.

As for mounting the SkyMaster 15x70s on a tripod, forget the supplied adapter. It is all-plastic garbage and induces a lot of wobble, as well as being prone to suddenly snapping under the weight of these binoculars. You can find an aftermarket all-metal adapter for less than $20. As for why they couldn’t include that instead of the supplied one, that is bizarre. Attaching the binoculars to a tripod with a metal adapter is a simple affair—just screw in your tripod’s ¼ 20 screw to the adapter, remove the small Celestron-logo cover on the binoculars, screw the knob on the adapter into the binoculars, and away you go.

Mounting Recommendations

The Celestron SkyMaster 15x70s need a tripod or mount of some kind to be used for extended astronomical observation, unless you are built like Arnold Schwarzenegger. If you rest your elbows on something to aim them handheld, you’ll probably be okay for short periods, but that is awkward and limits where you can point them. You’ll also be sure to want a metal tripod adapter to replace the one provided with these binoculars.

When considering a tripod, monopod, or other support for the SkyMaster 15x70s, ensure that it 

is capable of supporting the binoculars’ weight. Many readily available or budget-friendly options may not provide sufficient stability or maximum height for comfortable, wobble-free viewing. We’d recommend a monopod or a parallelogram mount, such as one from Orion, for the SkyMaster 15x70s. At 15x, the stability of a monopod, even one without a head equipped, is more than adequate while still allowing for a lot more freedom of movement at a low cost. A parallelogram is an ideal mounting, but it costs more than the SkyMaster 15x70s themselves.

Related Product Guide: Best Mounting for Astronomy Binoculars

Should I buy Used Celestron Skymaster 15×70 Binoculars?

One of the primary concerns when purchasing used SkyMaster 15x70s or any non-premium binoculars is the potential for them to be out of collimation. It is not advisable to buy a pair that you cannot test in person. Miscollimated binoculars typically display an easily noticeable double image on terrestrial objects at moderate distances, making it simple to identify this issue. Additionally, avoid used binoculars with any signs of fungus or deterioration, particularly if it is on inaccessible interior optical surfaces.

Alternative Recommendations

The Celestron SkyMaster 15x70s are decent, but the quality issues with them and their awkward size may elicit choosing an alternative option, probably with different aperture/magnification specs.

  • The Celestron SkyMaster Pro 15x70s are a high-quality option that address the quality control concerns of the more cheaply made SkyMaster 15x70s. They offer a sharp, wide field of view right out to the edges, and rarely, if ever, arrive out of collimation, while they can still be used somewhat comfortably handheld if you observe from a seated position.
  • The Celestron SkyMaster 12x60s are generally comfortable for handheld use, unlike their 15×70 counterparts, likewise featuring BAK-4 prisms and multi-coated optics for optimal light transmission, field of view, and eye relief without being too bulky.
  • The Bushnell Legacy WP 10x50s provide a wide 6.5-degree true field and are easy to use handheld. They are waterproof and fog-resistant, offering comfort, durability, and sharp views with their 20mm eye relief, twist-up eyecups, and eyepiece caps that stay attached to the neck strap.
  • The Zhumell 12×70 Astronomy Binoculars offer a wider field and slightly lower magnification than the SkyMaster 15x70s while otherwise sharing the same build. 12x70s like the Zhumells are more tolerant of collimation problems, need a less steady mount than higher power binoculars, and offer a slightly wider 4.6-degree field over the SkyMaster 15x70s’ 4.4 degrees.

What can you see with Celestron SkyMaster 15×70 Binoculars?

The Celestron SkyMaster 15x70s are ideal for stunning views of large open star clusters such as the Pleiades, the Double Cluster, and many others, as well as large asterisms like the Coathanger and nebulae like Orion (M42) and the North America Nebula under suitably dark skies. Globular clusters can be easily spotted with the SkyMaster 15x70s and are distinguishable from stars even at 15x magnification. These binoculars can reveal a few galaxies under dark skies, such as M31 and M33, though urban light pollution may hinder the visibility of fine detail or obscure galaxies altogether. In dark conditions, you may be able to see M31’s dust lane and companion galaxies, as well as hints of M33’s spiral arms. Many of the other brighter Messier and NGC galaxies are visible with the SkyMaster 15x70s in dark or moderately dark skies, including the Virgo Cluster. However, the 15x magnification of these binoculars won’t provide the ability to resolve much detail in these objects, and a 4” aperture equivalent isn’t going to provide a lot of light-gathering ability for galaxy observing anyway.

With their 15x magnification, the SkyMaster 15×70 binoculars allow you to discern Saturn’s largest moon, Titan, observe the various phases of Venus, and effortlessly detect Jupiter’s moons. Some observers can vaguely tell that Saturn has rings – though they appear more like the “ears” in Galileo’s early drawings with his telescope of similar magnification – and you may be able to just barely pick out Jupiter’s striking crimson equatorial cloud belts, but don’t expect it to be easy. The Moon’s larger geological features, including craters and expansive mountain ranges, are also visible with the SkyMaster 15x70s, though chromatic aberration may present a  significant annoyance. These binoculars can also separate some of the widest double star pairings, such as Albireo or the two pairs of Epsilon Lyrae. However, a high-quality telescope, even one with less light-gathering capacity, is generally more suitable for examining small and bright targets like the Moon, planets, and double stars, and can reveal the phases of Mercury, intricate details in galaxies and planetary nebulae, the Cassini Division in Saturn’s rings, Jupiter’s Great Red Spot, surface features on Mars, and other things that require magnifications of 30x or greater to really accomplish, a task the SkyMaster 15x70s are of course ill-suited for.

Zane Landers

An amateur astronomer and telescope maker from Connecticut who has been featured on TIME magazineNational GeographicLa Vanguardia, and Clarin, The Guardian, The Arizona Daily Star, and Astronomy Technology Today and had won the Stellafane 1st and 3rd place Junior Awards in the 2018 Convention. Zane has owned over 425 telescopes, of which around 400 he has actually gotten to take out under the stars. These range from the stuff we review on TelescopicWatch to homemade or antique telescopes; the oldest he has owned or worked on so far was an Emil Busch refractor made shortly before the outbreak of World War I. Many of these are telescopes that he repaired or built.

13 thoughts on “Unbiased Celestron Skymaster Giant 15X70 Binoculars Review”

  1. Mine did not have this “miscollimated” defect to any noticeable extent, due, in large part it seems, to mere luck. So it’s certainly worth the gamble.
    As far as the extent to which these are usable, much depends on experience. When the trick of averted vision is mastered even fainter “fuzzies” such as dim galaxies will begin to become not very difficult. By far the determining factor lies in the darkness and moonlessness of your site on any given night.

    • Agreed 100%. I am not a huge binocular guy but I do enjoy using my SkyMaster 15x70s occasionally, though my pair is miscollimated slightly and I have yet to bother trying to remedy it.

  2. Instead of throwing away the supplied PLASTIC tripod mount, it can be made stronger by simply filling in the recessed areas with JB WELD for a cheap quick fix. Why they skimped on the plastic in the first place is another mystery as well!

  3. just ordered the 17×70 cant wait to get my hands on them ! i will let you no what i think once i try them out ! RIO ………………….

  4. I agree about the supplied tripod mounting bracket. Too much flexure, causes objects to jiggle side to side. Get a good metal one, you’re images will be much steadier. Great views of the stars with these glasses. Open clusters are crisp and sharp. My pair is perfectly collimated. You’ll need a good tripod for stargazing. Great affordable binoculars!

    • Yes but Uranus/Neptune will look like stars and the galaxies in Virgo are faint fuzzies with little detail. A large telescope (10″ or bigger) is best for these objects


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