Celestron StarSense Explorer 8″ Review By Zane Landers
Celestron’s StarSense Explorer 8” Dobsonian is the latest entrant in the crowded market of beginner Dobsonian telescopes.
Celestron’s StarSense Explorer 8” Dobsonian offers a relatively basic set of features but with the aid of Celestron’s newest software technology to use your smartphone as a pointing device.
203mm (8″) Aperture
1200mm Focal Length
The StarSense Explorer 8” Dobsonian is, as the name implies a 8” (203mm) aperture Newtonian reflector on a Dobsonian mount, with a focal ratio of f/6 and a focal length of about 1200 mm. Its focuser is a 2” single-speed Crayford design, able to accept both 1.25” and 2” eyepieces with the included adapters.
Adjustable bearing friction for altitude axis
The StarSense Explorer 8” is pretty simple to set up – just plop the scope on the base, collimate it if you need to, and configure your phone with the StarSense Explorer app and bracket. The StarSense Explorer App is pretty straightforward in its guidance and will be able to aim you at thousands of objects such as galaxies, nebulae, star clusters, and Solar System objects with ease. There’s little else to say about it – it works very accurately and you’re unlikely to want to view something that isn’t in the app’s database. You push and pull the scope around the sky as with any Dobsonian, making small nudges to track objects at high magnification if needed.
1.25″ 25mm Plossl Eyepiece
Red dot finder
The included 25mm Plossl is good for low-power viewing of deep-sky objects, but you’ll need additional eyepieces for higher magnifications, which is useful for lunar and planetary viewing as well as smaller deep-sky objects and double stars. A wide-angle 2” eyepiece for low-power viewing might also be a good idea. So plan on upgrading this scope almost immediately after purchasing or just order some additional accessories at the same time.
What can you see?
The StarSense Explorer 8” has enough aperture to show you a lot within the Solar System. The phases of Venus and Mercury are easy to see, though neither planet is going to show any other details no matter how powerful your telescope is. Lunar details just a few miles across, like craters, ridges and mountain tops, are visible under almost any conditions. Mars shows its polar ice caps and a few dark regions. Jupiter’s 4 largest moons are easily visible, and at high power you can pick out the planet’s cloud bands and resolve the moons into disks – along with their shadows when they transit across Jupiter itself. The Great Red Spot can be seen as well, though it’s hard to detect oftentimes when it has a similar hue to the surrounding cloud belts.
Saturn’s rings are easy to see with any good telescope; with a higher-magnification eyepiece than the stock 25mm you can also resolve the Cassini Division within the rings and cloud banding on the planet itself. Saturn’s half dozen brighter moons appear as pinpoints. Uranus and Neptune are featureless and hard to distinguish from stars, but the StarSense Explorer technology will help you with correctly identifying them. At high magnification under fairly dark skies, one or two of Uranus’ moons can be faintly seen with the StarSense Explorer 8”, and Neptune’s moon Triton is a bit easier to spot.
Views of deep-sky objects are strongly dependent on the darkness of your night sky. Open star clusters shine even under light-polluted conditions, with hundreds of stars often displaying colors in big, easy-to-see groupings. Globular star clusters at low power appear as fuzzy balls and require high magnification for good views; under most conditions, an 8” Dobsonian like the StarSense Explorer should have no trouble resolving the brighter star clusters, such as M13 or M15, into hundreds of individual components.
Galaxies and nebulae are the deep-sky objects most affected by light pollution, and no telescope or accessory is going to get around that. Under light-polluted skies, the larger nebulae like the Orion Nebula (M42) or the Swan (M17) still look great with the StarSense Explorer 8”, though their beauty is diminished. Under dark skies, other large nebulae are a lot easier to see, especially with a good UHC nebula filter. Small planetary nebulae like the Ring (M57) and Dumbbell (M27) look good under almost any conditions.
Galaxies vary in size, shape, brightness, and contrast. With dark skies, you can begin to resolve the spiral arms and H-II regions of galaxies like M51, M33, and M101. Under moderately light-polluted skies, the dust lanes in galaxies like M104, M64, or the Andromeda Galaxy, M31, are still fairly easy to see. Scores of galaxies with no features at all – dim spirals or boring ellipticals – are also visible with the StarSense Explorer 8”, and some occur in pairs or groups – such as the Leo Triplet containing M65 and M66, the four elliptical companions to the Andromeda Galaxy, or the gigantic Virgo Cluster, a vast region containing dozens of galaxies which can be observed with the StarSense Explorer 8” under dark skies.
SVBONY 34mm SWA
Agena 15mm Starguider
SVBONY 6mm Redline
The StarSense Explorer 8” Dobsonian certainly needs more eyepieces to complement its single 25mm Plossl ocular. For low power, the simple Erfle-type design of the SVBONY 34mm SWA works fine at f/6, and the eyepiece will provide a mere 35x and a huge 2-degree true field with the StarSense Explorer 8”. The Agena 15mm Starguider is comfortable to use and sharp, providing 80x, while the 6mm redline provides a nice high magnification of 200x – perfect for lunar, planetary, and double star viewing.
Heavy eyepieces can pose a problem for balance with the StarSense Explorer Dobsonians as the center of gravity can shift to well outside the scope’s altitude bearing axis and cause the scope to slowly droop over. As a solution, Celestron has added a pair of clutches which can be tightened to prevent the scope from moving in altitude. However, doing so results in jerky and less-than-smooth movements which are rather detrimental to using the scope. The long-term solution would be to add a counterweight of some kind to the back of the scope. However, this is inconvenient and unsightly.
The other major disadvantage is, quite simply, what you get for the price. Or rather, what you don’t get. The StarSense Explorer 8” is a bare-bones instrument with only one eyepiece, a single-speed focuser and only 8” of aperture at a price significantly higher than the most well-accessorized competitors and around that of a similarly Spartan 10” scope. You’re paying a multi-hundred-dollar premium for some carrying handles, a plastic phone bracket, and an app which makes aiming the scope a bit easier. Whether this is worth it is up to you, but a cheaper 8” scope will allow you to spend more on accessories and a 10” Dobsonian will show you more for a similar price tag.
Overall, the Celestron StarSense Explorer 8” Dobsonian is a good scope, and works exactly as advertised. However, do consider the value for the money compared to other telescopes, and whether the price tag is really worth the relatively slight convenience of the StarSense Explorer pointing aid.