The Optical Tube
The optical tube of the Celestron StarSense Explorer 114mm Dobsonian is a 114mm f/3.9 Newtonian reflector, thus having a focal length of 450mm. A Newtonian reflector with a fast focal ratio such as f/3.9 naturally exhibits a fair amount of coma. Unfortunately, with this instrument, it’s a problem that has to be tolerated given the non-existence of a 1.25” coma corrector, which, even if available, would cost more than the StarSense Explorer 114mm itself. On the upside, coma mainly affects the widest field of view and lowest magnification. Thus, when observing many celestial targets, you would typically use a medium magnification, effectively minimizing the coma issue.
Unlike many small reflecting telescopes, including much of Celestron’s own lineup, the Celestron StarSense Explorer 114mm Dobsonian offers easy collimation. Its parabolic primary mirror is subjected to quality control measures ensuring sharp, clear images of celestial bodies such as the Moon, planets, nebulae, galaxies, and stars.
The focuser on the StarSense Explorer 114mm Dobsonian is a 1.25” rack-and-pinion unit, predominantly composed of plastic. Despite its simplicity, it performs its duty well. Some units may experience a slight wobble during focusing, but this can be rectified by strategically positioning tape strips on the drawtube and applying a good-quality grease or lubricant to the rack and pinion teeth.
Although primarily designed as a wide-field instrument, the StarSense Explorer 114mm excels at lunar and planetary viewing, far surpassing the 60-90mm refractors frequently recommended to beginners. Naturally, it’s an undisputed winner when it comes to observing deep-sky objects.
The StarSense Explorer 114mm Dobsonian comes with two 1.25” Kellner eyepieces: a 17mm and a 10mm unit providing 24x and 45x magnification, respectively. Although these eyepieces are of acceptable quality, neither includes a rubber eyeguard. Both oculars have a roughly 50-degree apparent field of view. Due to this scope’s fast focal ratio, the 17mm eyepiece may display some edge-of-field aberrations, and the 10mm eyepiece can feel somewhat uncomfortable for viewing on account of its short eye relief. Both also have a little bit of chromatic aberration. However, as with any quality telescope, you can swap out the included eyepieces for any 1.25” eyepieces of your preference. The supplied eyepieces are sufficient for beginners.
For precise aiming, a red dot finder is included, allowing you to easily aim the StarSense Explorer 114mm by hand precisely at targets without the use of the StarSense Explorer technology.
The mount design utilized by the StarSense Explorer 114mm is that of a single-arm tabletop “Dobsonian” mount. The exact definition of a Dobsonian is a contentious topic among amateurs nowadays, as the altitude bearing of the StarSense Explorer 114mm doesn’t rely on gravity the way a traditional Dobsonian does. The mount moves from side to side on three small plastic pads. The large plastic nut on the altitude axis can adjust the friction and thus force required to move the telescope up/down, while adjusting the azimuth tightness requires a pair of wrenches, pliers, or a socket wrench.
Although the StarSense Explorer 114mm Dobsonian is designed for use on a tabletop, it can be used with other options. It won’t fit on a photo tripod like smaller instruments, but alternatives like a milk crate, barrel, bar stool, car hood, or a homemade wooden stand can serve the purpose.
Celestron does sell a tripod for use with the StarSense Explorer tabletop telescopes, but it’s so expensive that if you are considering purchasing it, you might be better off just buying a larger and more capable telescope, such as a larger StarSense Explorer model.
Celestron’s StarSense Explorer Technology
Fundamentally, the Celestron StarSense Explorer employs a relatively old technology known as plate-solving. Essentially, it captures an image of the sky and uses computer algorithms and star maps to determine its orientation. This technique is typically utilized for astrophotography to bypass the lengthy process of GoTo alignment and is used to locate a single target.
The StarSense Explorer consists of a bracket to aim your phone at a small mirror, aligned with the telescope mount, and a free app that you can download to any smartphone or tablet. It uses your phone’s onboard camera and processing power to perform plate-solving. Setup is straightforward: After a quick alignment procedure to make sure the phone, bracket, and telescope are parallel, the app helps in locating thousands of deep-sky objects (as well as minor planets, comets, etc.) by displaying arrows superimposed on a map of the sky until you are about centered on it. It accomplishes this by tracking and indicating your telescope’s orientation in real-time using your phone’s camera and gyroscope data. The StarSense Explorer system’s accuracy is limited to slightly better than 0.25 degrees, or half the width of a full moon. While this is less accurate than a genuine GoTo system or encoder-based digital setting circles, it is precise enough for locating most deep-sky objects.
Should I buy a Used Celestron StarSense Explorer 114mm Dobsonian?
The Celestron StarSense Explorer 114mm Dobsonian, if procured used, is bound to be a terrific instrument, provided you get the code and StarSense Explorer bracket needed to use the StarSense Explorer features. Considering their relatively recent production, it’s unlikely that you will encounter one with mirror coatings in a poor state. It’s crucial to note that purchasing a StarSense Explorer 114mm with damaged mirrors isn’t a viable option as the cost of recoating surpasses the price of a brand-new telescope. Replacement of missing eyepieces or a missing finder might not be as concerning, but again, make sure the aggregate cost doesn’t exceed the cost of a new unit.
Alternative Recommendations (USA)
The Celestron StarSense Explorer 114mm Tabletop Dobsonian isn’t exactly our first pick in its price range; you may want to check out some of these other Dobsonians, which offer better performance and/or a lower price tag:
- The Sky-Watcher Heritage 150P’s 6″ aperture provides a 33% resolution boost and offers more than 80% more light-collecting power than the StarSense Explorer 114mm, while also featuring a collapsible tube to keep it compact when not in use. Like the StarSense Explorer 114mm, it utilizes a single-armed tabletop Dobsonian mount.
- The Sky-Watcher Heritage 130P, essentially a smaller 150P, outperforms the StarSense Explorer 114mm slightly in terms of light-collecting area and resolving power. It also features an ultra-compact collapsible tube and a user-friendly tabletop Dobsonian mount.
- The Zhumell Z130 Tabletop Dobsonian features the same optics as the Heritage 130P but with an enclosed tube atop a tabletop Dobsonian mount. The Celestron StarSense Explorer 130mm Dobsonian is identical to the Z130 but features the StarSense dock added on, like the 114mm model.
- The Orion StarBlast 4.5 Astro Tabletop Dobsonian and the Zhumell Z114 are identical to the StarSense Explorer 114mm Tabletop Dobsonian in every way, apart from the lack of StarSense Explorer tech and the StarBlast’s slightly different accessory bundle.
- The Apertura AD8/Zhumell Z8/Orion SkyLine 8 trumps the StarSense Explorer 114mm with its light-gathering capacity, offering more than three times the capability. It also provides close to double the resolving power, turning formerly “faint fuzzy” deep-sky objects into clear and detailed wonders. Its dual-speed focuser, included eyepieces, built-in cooling fan, and adjustable bearings for balance round up its offerings, making it excellent value for its price.
- The Celestron StarSense Explorer 8” Dobsonian offers splendid views of the Moon, planets, and deep-sky objects, as can be expected of any good 8″ Dobsonian. It features a weight-optimized base and the Celestron StarSense Explorer technology, facilitating easy night sky navigation using your smartphone. Despite its solid performance, it lacks additional features and accessories. An equally high-performing 10″ model is also available, adding another choice for prospective buyers.
- The Sky-Watcher Virtuoso GTi 150P stands out as a unique hybrid manual/GoTo scope. Essentially a computerized Heritage 150P, it features a tabletop Dobsonian mount, while the collapsible tube design significantly increases portability. Notably, it also comes with full computerized functionality, complete with motorized tracking and aiming managed via your smartphone. However, thanks to its FreedomFind encoders, manual adjustments remain an option.
- The Orion SkyQuest XT6 Dobsonian is a freestanding 6” f/8 telescope. The longer f/ratio of f/8 allows for easier collimation and removes coma, albeit at the expense of a narrower maximum field of view and a bulkier tube assembly.
- The Orion StarBlast 6 shares many similarities with the Heritage 150P, albeit with a full-length optical tube and a rack-and-pinion focuser replacing the helical unit.
- The Celestron Astro Fi 130mm is a fully motorized, tracking GoTo telescope operated via your smartphone or tablet. Its 5.1″ aperture delivers commendable views, though for the price you could get a larger Dobsonian with greater capabilities.
Aftermarket Accessory Recommendations
A 6mm “gold-line” or “red-line” eyepiece, offering 75x magnification, would be a perfect addition to enhance your eyepiece collection for the Celestron StarSense Explorer 114mm on the higher magnification end. Moreover, a 2x Barlow lens will enable you to increase the magnification to 150x, which is approximately the maximum capability of the StarSense Explorer 114mm.
For low magnification, a 25mm Plossl gives 18x magnification and a field of view of 3 degrees. A 27mm BST Flat-Field will provide a sharper, wider field of 3.8 degrees—nearly eight times the angular diameter of the full moon—and a magnification of 17x, about as low as you can go.
Additional eyepieces within the 9–15mm range could further expand your magnification possibilities, such as a 9mm redline or goldline (50x) and a 15mm SWA or redline (30x). However, these can add up to quite a bit of extra cost, which could go towards a larger scope or a good nebula filter instead.
Lastly, another accessory to consider is the 1.25” Orion UltraBlock UHC nebula filter. While it doesn’t “filter out” light pollution per se, it enhances contrast on nebulae, making them appear brighter against the backdrop and revealing intricate details. This filter works wonderfully with the StarSense Explorer 114mm, which can display expansive areas of the sky containing regions like North America, Veil, Lagoon, Trifid, Swan, and Eagle Nebulae. Even under a dark sky, a UHC filter enhances contrast on these objects by darkening the sky background.
What can you see with the Celestron StarSense Explorer 114mm tabletop Dobsonian?
The effectiveness of the Celestron StarSense Explorer 114mm Dobsonian for observing deep-sky objects is, like all telescopes, considerably influenced by the surrounding light pollution conditions. Nevertheless, it’s worth noting that even in cities or suburban areas, certain celestial objects remain readily visible. Prime examples of these are open star clusters such as the Double Cluster or the Pleiades (M45), which can typically be discerned quite easily even under very bright skies.
The extensive field of view of the StarSense Explorer 114mm Dobsonian makes it a superb instrument for low-power sweeping of the cosmos, particularly along the brighter sections of the Milky Way. You can effortlessly locate many exciting open clusters and numerous bright emission nebulae. Using a nebula filter or under a dark sky, the enormous Rosette and Veil nebulae span across the entire field of view at low magnification.
With the StarSense Explorer 114mm, you can challenge yourself to spot the various dark nebulae crossing the summer Milky Way under dark skies. The dust lane of the Andromeda Galaxy is easily visible with a wide-field scope like this. However, due to the modest 114mm aperture, other galaxies may not offer significant details. Bright emission nebulae like Orion, the Lagoon, and the Swan look splendid, especially from dark skies or with a UHC filter. Under sufficiently dark skies, viewing the Veil Nebula with an oxygen-III or UHC filter is a fascinating experience.
Unfortunately, the resolution and light-gathering capabilities of the StarSense Explorer 114mm limit the views of globular star clusters to blurry orbs without individually resolved stars, but double stars and open clusters are fantastic targets to view with this telescope.
Despite being an f/3.9 “light bucket,” the sharp optics of the StarSense Explorer 114mm make it an unexpectedly excellent lunar and planetary instrument. Collimation might require some patience, and you’ll need a short focal length eyepiece or Barlow lens to achieve high magnifications, but the resulting sharp and detailed views will rival those of a high-end small refractor. This telescope effortlessly captures the phases of Venus and Mercury, the Moon’s tiny craters and mountains, and the ice caps on Mars.
During Mars’ biannual close approach, opposition, the Red Planet displays dark markings on crisp, steady nights at high magnification with this telescope. Observing the outer moon Deimos at favorable times is also possible.
With the Celestron StarSense Explorer 114mm Dobsonian, you can observe the four Galilean moons of Jupiter, along with their clearly visible disks and pitch-black shadows, during their transits in front of the planet. Jupiter’s vibrant storms, cloud belts, and the notorious Great Red Spot can be seen, providing an ever-changing panorama that varies in appearance week after week. However, even at high magnification, the Great Red Spot might be challenging to identify on a night with less-than-optimal steadiness due to its persistent shrinkage over the years.
The Celestron StarSense Explorer 114mm Dobsonian offers a captivating view of Saturn’s rings and the slender Cassini Division within them. In addition, it’s also possible to make out various other features on the gas giant. These include Saturn’s cloud belts, its shadow cast upon the rings, and several of its moons, like Titan, Rhea, Tethys, and Dione.
Uranus and Neptune appear as tiny dots with a small 114mm telescope, nearly indistinguishable from stars at low power, and their faint moons are invisible to even the skilled eye. Finding these two planets can be somewhat challenging, but the StarSense Explorer technology makes it easy to identify both ice giants. The distant and faint dwarf planet Pluto is far beyond the reach of the StarSense Explorer 114mm Dobsonian, requiring at least twice as much aperture to be spotted even under dark skies.