The Optical Tube
The StellaLyra 12” f/5 Dobsonian is a 12” (304mm) f/4.9 Newtonian reflector with a resulting focal length of 1500mm. With its 1.5-meter (58”) long tube, you won’t be able to fit it lengthwise across the back of most vehicles, which means you’ll have to fold down a seat to transport this scope anywhere. The tube also weighs about 22 kg, which combined with its length and girth can make carrying it difficult. Lifting straps of some sort, or moving the entire assembled telescope on a dolly, are good ideas.
Contrary to smaller aperture Dobsonian telescopes, the StellaLyra 12” boasts a rather thin mirror that necessitates a robust flotation mirror cell. The primary mirror is supported by a 9-point mirror cell: three loose triangular structures, each touching the mirror at three points, which effectively distribute its weight to prevent sagging due to gravity. The collimation process remains unchanged from most smaller Dobsonians, incorporating three spring-loaded knobs and the ever-present three redundant locking bolts at the back end, which would be wise to remove from the telescope before they inflict damage to the primary mirror or cause other issues.
The primary mirror of the StellaLyra 12″ f/5 Dobsonian is crafted from BK7 glass, which demands a considerable amount of time to acclimatise to ambient temperature when transferred from a warm indoor environment or following prolonged exposure in a hot vehicle. While the built-in cooling fan offers some relief, you should anticipate spending a fair amount of time waiting for the telescope to deliver crisp and sharp views.
The secondary mirror of the StellaLyra 12″ f/5 Dobsonian requires a hex key for making collimation adjustments, although it will rarely be necessary. Substituting the hex screws with thumb screws is not advised, as they are more prone to loosening and causing collimation to shift when the scope is transported or otherwise not in use.
The StellaLyra 12″ f/5 Dobsonian comes fitted with GSO’s standard 2-inch dual-speed Crayford focuser. The Crayford focuser design operates by rolling the focuser draw tube against a set of four rollers and a piece of Teflon (PTFE) plastic, devoid of gears, teeth or other components in the 10:1 reduction knob. The focuser features a brass compression ring that securely holds your eyepieces without causing any scratches, and it also includes a 1.25-inch adapter with filter threads and a compression ring fitting as well as a 35mm length, 2” extension tube, which is also threaded for filters and uses a compression ring. This extender is required for most eyepieces to reach focus unless you are using a coma corrector.
The StellaLyra 12″ f/5 Dobsonian telescope is accompanied by a 9x50mm right-angle finder scope and a pair of eyepieces: a 2-inch barrel, 30mm focal length “SuperView” or SWA Erfle eyepiece (50x) and a 1.25-inch, 9mm Plossl (167x).
The included GSO 30mm SuperView 2” eyepiece, yielding 50x magnification with the StellaLyra 12″ f/5 Dobsonian, is excellent for low-magnification views of deep-sky objects and the Moon. The apparent field of this eyepiece is approximately 68 degrees. Stars at the edge of the field of view with the SuperView and other similar budget-friendly wide-angle oculars might appear distorted into “seagulls” or cross-like blurred shapes in the StellaLyra 12” f/5 Dobsonian due to a combination of the telescope’s inherent coma, which impacts all faster Newtonians, and the SuperView’s optical design. The simple 5-element Erfle optical configuration used by the SuperView and similar wide-angle eyepieces is just not designed for fast focal ratios below f/6 or so, leading to the issue of edge-of-field astigmatism, which actually hides the coma inherent in the StellaLyra 12” f/5 which cannot be removed without an additional coma corrector. However, the SuperView delivers considerably sharper views, as much as a much wider true field encompassing a larger area of sky, compared to standard 25mm Plossl or Kellner eyepieces and is more comfortable to observe through than those designs.
The other eyepiece supplied with the StellaLyra 12″ f/5 Dobsonian, a 9mm focal length 1.25-inch Plossl, provides 167x magnification. With limited eye relief, as is always the case with short focal length Plossl and Kellner-type eyepieces, you will need to press your eye against it to take in the entire field of view at once, making it completely unusable for eyeglasses wearers and feeling rather uncomfortable. The apparent field of view of this eyepiece is also only around 45 degrees, which is narrow by any standard and almost claustrophobic compared to the 30mm SuperView’s 68-degree apparent field. Nevertheless, it is quite sharp and offers an ideal magnification for observing smaller targets such as the Moon, planets, double stars, globular clusters, and planetary nebulae. However, on a sufficiently steady night, the StellaLyra 12″ f/5 Dobsonian can accommodate much higher magnification with additional eyepieces.
Even under heavily light-polluted skies, the well-constructed 9×50 finder performs remarkably well, unveiling many fainter stars that are invisible to the naked eye, as well as numerous bright deep-sky objects. However, beginners might find it difficult to coarsely aim at a target, as it is not possible to look up at the sky and through the finder simultaneously, and the crosshairs are challenging to see in the dark without any sort of illuminated reticle device. Mastering the technique of sighting along the tube and then glancing through the finder to pinpoint your target without significantly overshooting it requires some practice and may be frustrating. If you struggle to use the 9×50 finder, you may want to supplement or replace it with a red dot finder, Telrad, or a similar zero-power reflex sight, which does not offer the ability to reveal faint stars and deep-sky objects but is far more intuitive to use.
The StellaLyra 12″ f/5 Dobsonian, like all Dobsonians, is an alt-azimuth-mounted telescope. It moves up and down on two side bearings attached to the tube and swivels sideways by spinning the top part of the base against the bottom. However, unlike other Dobsonians that use plastics, the StellaLyra 12″ f/5 Dobsonian employs bearings akin to those found in industrial machinery. This works acceptably, but has some downsides as we will explain.
For side-to-side motion, the StellaLyra Dobsonians utilise roller bearings, functioning like a “lazy Susan” with small plastic rollers between the telescope’s ground board and the bottom face of the rocker box. This system is inexpensive, smooth and largely effective, but it can be loose and easily spun on a windy night, or simply cause you to overshoot your target when adjusting the telescope’s pointing direction. Similarly, tightening the centre bolt can make motions overly sticky and difficult to control. Achieving the precise degree of friction needed can be challenging, which is why Dobsonians typically use Teflon bearings gliding against a laminate surface like the melamine already covering the StellaLyra 12” f/5 Dobsonian’s base. Replacing the lazy Susan with furniture glides or PTFE (Teflon) pads, as used in ordinary Dobsonians, is an affordable and easily implemented solution.
The StellaLyra 12” f/5 Dobsonian’s altitude bearings are sealed ball bearings with large plastic knobs for adjusting friction, which influences the ease of moving the telescope up and down in the sky. The bearings can be tightened to lock the telescope in place for storage or when swapping out heavy accessories. You can also slide them along the tube depending on where the centre of gravity lies with your usual accessory setup. It is advisable to set both bearings’ positions in advance indoors, as evenly adjusting them in the field can prove challenging.
The base of the StellaLyra 12″ f/5 Dobsonian weighs around 17 kg due to its particle board construction rather than a genuine wood material. Consequently, it is denser and more challenging to manoeuvre than one might initially expect. The base is delivered flat-packed and can be assembled quickly using the provided screws and tools. However, frequent usage can cause wear and tear on the particle board base, with moisture exacerbating its deterioration, especially in humid environments or if mishandled. If this happens, you can create a replacement base from plywood using relatively simple carpentry tools. Besides improved durability, substituting the stock particle board base with a lighter plywood alternative can make the telescope more manageable for those who might find its weight and size detrimental to set up or use. Another option is to place the scope on a cart or dolly to facilitate transportation.
Should I buy a Used StellaLyra 12″ f/5 Dobsonian?
If you’re seeking a high-quality, large aperture telescope at an affordable price, a used StellaLyra 12″ f/5 Dobsonian is as sound a choice as a new scope if you can find one available and you can put more of your budget towards accessories thanks to the discount if buying used. When buying a used Dobsonian telescope of any brand or design, watch out for damaged mirror coatings or a damaged base. A damaged base is relatively simple and inexpensive to replace provided you have access to plywood and some basic carpentry tools, and a homemade one may offer additional benefits as previously discussed, but damaged mirror coatings can present a more significant issue. If the mirror appears dull, a good wash with dish soap and distilled water might be all that’s required. However, if there is evident mossy or spider-like fungal or chemical corrosion, pinholes, or a transparent look to the coating, recoating the mirror might be necessary, which can be expensive. Weigh the cost of recoating against the cost of purchasing a new instrument before making a decision. At this aperture, moderate damage to the coatings may still not hinder the scope’s performance enough to bring it down to a 10” equivalent in light gathering and you’re still getting the full resolution of a 12”, so if a used but worn 12” is the same cost as a new 10” to you by all means get the 12” if you’re up for it. Recoating can always wait.
Don’t be overly concerned about dents in the tube of any used Dobsonian – they’re almost inevitable, and most don’t affect the light path. If any dents do impact the optics, they can often be removed with tools like those used for car dent removal, or even with a plunger or hammer in some instances.
The StellaLyra 12″ f/5 Dobsonian is among the finest beginner telescopes on the market, and certainly one of the best deals for a 12” Dobsonian, offering outstanding quality and value for its price. However, you may want to consider alternative Dobsonian options, including larger, smaller, truss/collapsible tube or motorised variants.
- The StellaLyra 10″ f/5 Dobsonian, as with its larger 12” counterpart, offers outstanding value for a 10″ Dobsonian, boasting an extensive array of features and accessories that distinguish it from competitors. Its performance matches that of collapsible or truss-tubed 10″ Dobsonians without necessitating additional purchases, such as a shroud.
- The Explore Scientific 10″ Ultra Light Dobsonian provides a more compact design compared to solid-tubed Dobsonians or Sky-Watcher FlexTube models due to its full truss tube assembly, rendering it an appealing option for those in search of a portable telescope. However, it requires more assembly effort and comes with fewer accessories.
- The Celestron StarSense Explorer 8″ Dobsonian ensures straightforward setup and navigation with its lightweight base and StarSense Explorer technology, but it only includes basic accessories and features and carries a relatively high price tag compared to other 8″ models.
- The Sky-Watcher Virtuoso GTi 150P is a compact, miniaturised GoTo Dobsonian, featuring a collapsible strut tube, GoTo system, and FreedomFind encoders in a small, lightweight, and wide-field 6″ f/5 package. It can be used on a tabletop or attached to a photo tripod. The manual Heritage 150P is identical, except for lacking a tripod stud at the bottom and electronics, but offers the same form factor and excellent views through the eyepiece.
- The Sky-Watcher Skyliner 300P FlexTube Dobsonian is easier to transport than solid tube scopes like the StellaLyra 12″ and simpler to set up than truss telescopes. However, it comes with a questionably designed Dobsonian mount with undersized non-adjustable altitude bearings, which will inevitably lead to balance problems when pairing this telescope with heavy wide-angle eyepieces or a coma corrector.
- The Explore Scientific 12″ Truss Tube Dobsonian is a high-quality 12” Dobsonian telescope with a dual-speed Crayford focuser and an optimised all-metal structure that occupies minimal space when disassembled, while also offering smooth manual movements. However, it does not include useful eyepieces or a finder, which you will need to purchase separately. Additionally, this scope requires extra add-ons like a shroud to function optimally.
- The Celestron StarSense Explorer 10″ Dobsonian is a lightweight and portable option among 10″ Dobsonians, employing Celestron’s StarSense Explorer technology with your smartphone to assist in locating deep-sky objects. However, it lacks the extensive features and accessories provided by the StellaLyra Dobsonians.
- The StellaLyra 16″ f/4.5 Dobsonian delivers considerably enhanced performance compared to the StellaLyra 12” f/5 Dobsonian due to its larger aperture, and its full truss tube can be disassembled into relatively manageable subcomponents. Although this telescope is a behemoth, it offers stunning views of deep-sky objects.
- The Sky-Watcher Skyliner 350P FlexTube Dobsonian is somewhat larger and taller than the StellaLyra 12” f/5 Dobsonian, and whilst its 14″ primary mirror doesn’t provide a substantial increase in performance compared to the a 12” Dobsonian, it remains superior for deep-sky observation if you can tolerate the bulkiness of the tube and base.
- The Sky-Watcher Skyliner 300P FlexTube GoTo Dobsonian is heavier and costlier than the all-manual 300P but features fully motorised tracking and GoTo, as well as the Sky-Watcher FreedomFind encoder system to enable manual aiming. It is also roughly the same physical size as the non-GoTo 300P FlexTube.
- The Sky-Watcher Skyliner 250P FlexTube GoTo Dobsonian is somewhat more compact than a traditional solid-tube 10″ Dobsonian, offering fully motorised tracking and GoTo functionality, along with of course the FlexTube design.
Aftermarket Accessory Recommendations
With a large, costly Dobsonian telescope like the StellaLyra 12” f/5 Dobsonian, there is an enormous range of eyepiece options available, but we have selected a few for your convenience as well as provided a few other accessory recommendations.
For low-power observation, the StellaLyra’s provided 30mm SWA/SuperView works fine, but a 28mm UWA (54x) or another high-quality UWA or XWA eyepiece within the 20-30mm range, such as the Explore Scientific 82-degree or 100-degree series, will provide an even wider field of view with fewer aberrations than the 30mm SuperView, and works particularly well if used in conjunction with a suitable coma corrector like the Explore Scientific HRCC or Baader MPCC.
For higher magnifications, we advise acquiring at least another two or three eyepieces, such as a 16mm UWA (94x) and a 7mm UWA (214x), for the StellaLyra 12” f/5 Dobsonian. This provides a respectable range of magnifications for observing the Moon, planets, double stars, and smaller deep-sky objects like planetary nebulae and globular star clusters. Furthermore, if your atmospheric conditions permit such high magnifications, you might want to consider a 4mm UWA or planetary eyepiece (375x). A good collimation tool such as a Cheshire is also crucial for achieving sharp images with the StellaLyra 12” f/5 Dobsonian.
Aiming the StellaLyra 12” f/5 Dobsonian may prove challenging with only the supplied right-angle finder. While it’s precise once you’ve located the general area of your target, the right-angle nature of the provided 9×50 finder scope makes it difficult to initially aim at the correct patch of sky, and it’s quite easy to get lost. A Telrad or Explore Scientific ReflexSight works well in conjunction with the 9×50 finder or can even entirely eliminate its use.
As we often recommend, a narrowband Ultra High Contrast (UHC)/OIII nebula filter is one of the most valuable tools for deep-sky observation with any large Dobsonian telescope. It can significantly enhance the contrast of numerous nebulae, such as the Orion Nebula, when used with virtually any telescope, including the StellaLyra 12” f/5 Dobsonian. This filter also improves the visibility of planetary nebulae by reducing the brightness of nearby stars, making it easier to spot them at low power. Moreover, it provides sufficient contrast enhancement to reveal previously indistinguishable nebulae like the Crescent Nebula, Veil Nebula, or Flame Nebula when using the StellaLyra 12” f/5 Dobsonian under dark skies.
What can you see?
With the StellaLyra 12” f/5 Dobsonian, you can observe many deep-sky objects and spectacular details that those with smaller scopes can only wish they could see. The best views require a clear and dark night sky away from city lights, which is why we emphasise ensuring you can easily and safely transport this colossal telescope. If you can’t see the summertime Milky Way when you look up, the StellaLyra 12” f/5 Dobsonian will likely disappoint on galaxies under those viewing conditions, and the views of most other deep-sky objects – especially nebulae – will be significantly diminished by light pollution or outright washed away depending on the severity.
The StellaLyra 12” f/5 Dobsonian will have no difficulty resolving even the more challenging globular clusters into individual stars under dark skies, as well as the more well-known ones like M13 and M15 under almost any viewing conditions. Due to its large aperture, the StellaLyra 12” f/5 Dobsonian can also display the spiral arms and dust lanes of dozens of the brightest galaxies—and reveal thousands upon thousands more, assuming you have good skies. The spiral arms of M51 are clearly visible at medium power, as are the H-II regions that dot the spiral arms of M33. The Andromeda Galaxy, M31, spans several fields of view. You can observe an open cluster called NGC 206 inside it, as well as a small globular cluster called G1 a few degrees away, though both of course require dark skies to be viewed.
With the StellaLyra 12” f/5 Dobsonian, even under light-polluted skies, you’ll be able to observe thousands of open star clusters, many of which feature colourful stars, dust lanes, or are embedded within larger nebulae or clusters themselves. They appear magnificent, even under urban skies. These clusters range from compact and colorful formations such as M11 and M35 to looser gatherings like the Pleiades (M45).
The StellaLyra 12” f/5 Dobsonian also unveils dozens of planetary nebulae, many exhibiting fascinating colours and intricate details. These nebulae are so bright that they look fantastic even under suburban and city skies. Planetary nebulae vary from the expansive, bluish Dumbbell and Ring to the tiny, emerald-green Cat’s Eye. Some, like the Blinking Planetary Nebula, have easily visible white dwarfs at their centres, while others do not.
Emission nebulae such as Orion (M42) are jaw-droppingly detailed with the StellaLyra 12” f/5 Dobsonian, particularly under dark skies and when using a UHC filter. Unfiltered and under decent conditions, M42 appears to have a greenish or even slightly pink colouration. You’ll also be able to see the Veil Nebula supernova remnant with the StellaLyra 12” f/5 Dobsonian under dark skies.
The StellaLyra 12” f/5 Dobsonian is excellent for observing the Moon and planets as well. You can expect to discern the phases of Mercury and Venus, ice caps and dark markings on Mars, and a plethora of details on the Moon. Jupiter’s cloud belts and Great Red Spot look fantastic, and when the seeing conditions allow, you can easily resolve the disks of its moons, their shadows during transits, and even some features on Ganymede and Io.
Saturn’s rings and the Cassini Division within them are stunning, and under optimal conditions, the Encke Gap in the rings is also visible. Half a dozen moons accompany Saturn when viewed through a 12″ telescope, and you can observe some cloud banding on Saturn itself, along with the orange-gold disc of Titan. The blue-green orb of Uranus can be resolved, together with at least a couple of its moons under dark and steady skies, while Neptune’s blue disk often appears fuzzy, but its moon Triton is readily noticeable. Lastly, under dark skies, Pluto is a relatively easy catch in the StellaLyra 12” f/5 Dobsonian, appearing as a star-like point.