The Optical Tube
The StellaLyra 8” f/6 Dobsonian’s primary mirror is a 203mm (8”) f/5.9 unit with a resulting 1200mm focal length. It utilizes standard BK7 glass, which expands and contracts with temperature less than ordinary plate glass but not as little as borosilicate or Pyrex glass. As such, when exposed to extreme temperature variations, such as bringing the telescope outdoors on a freezing night, it may require more than half an hour to cool down and provide sharp images. Therefore, a small battery-powered fan has been installed on the back of the scope by default to help speed up this process. The primary mirror is easy to collimate, but it is highly recommended that you remove the “mirror lock” bolts from the back of the mirror cell, as they can be confusing during collimation, and if the telescope is dropped, they could potentially damage the mirror. This may further require replacing the springs to compensate for the stock ones’ lac of stiffness, which is why the locking bolts are attached in the first place. The StellaLyra 8” f/6 Dobsonian’s secondary mirror adjustment requires a hex key, although it should not need frequent adjustments. Replacement aftermarket thumb screws are not recommended as they tend to come loose more easily.
The StellaLyra 8” f/6 Dobsonian is outfitted with GSO’s standard 2-inch dual-speed Crayford focuser. It is frequently utilized with various Dobsonian, Newtonian astrographs, Cassegrains, and Ritchey-Chretien instruments offered by various retailers and is of decent construction. The Crayford focuser operates by rolling the focuser draw tube against a set of four rollers and a Teflon (PTFE) plastic strip, without any gears or teeth besides the planetary gears in the 10:1 speed reduction knob used for fine focusing adjustments. The focuser has a brass compression ring that holds eyepieces securely and gently, without scratching them. Furthermore, it includes a 1.25-inch adapter with filter threads, allowing you to use 2” filters with your 1.25” eyepieces, and a matching compression ring fitting.
The tube of the StellaLyra 8” f/6 Dobsonian is lengthier than that of some other 8” scopes on the market, such as the 8” f/6 Dobsonians marketed by Sky-Watcher/Celestron, among others. As a result, it may not fit in the trunk/boot of as many vehicles but should be fine across most back seats or laid diagonally.
The StellaLyra 10-inch f/5 Dobsonian telescope is bundled with a 9x50mm right-angle finder scopeand two eyepieces: a 2-inch, 30mm focal length “SuperView” (42x) and a 1.25-inch, 9mm Plossl (139x).
The 2-inch SuperView eyepiece, a 5-element Erfle type offering 40x magnification with the StellaLyra 8″ f/6 Dobsonian, is an outstanding eyepiece for low magnification with this telescope. The apparent field of view is approximately 68 degrees, which is quite wide and immersive. You might notice that stars on the edge of the field of view look slightly distorted into “seagulls” or cross-like shapes because of the SuperView’s optical design, which has moderate performance issues in telescopes faster than f/8, but it is of little detriment to the overall view. Nonetheless, the SuperView provides much sharper and wider views than a standard 25mm Plossl eyepiece and is more comfortable to use.
The provided 9mm Plossl eyepiece provides 133x magnification with the StellaLyra 8” f/6. It has limited eye relief, making it necessary to place your eye against it to view the entire field of view. The apparent field of view is about 45 degrees, much narrower than the SuperView’s 68-degree field of view. Nonetheless, it is plenty sharp and is appropriate for viewing small targets such as the Moon, planets, double stars, globular star clusters, and planetary nebulae.
The well-constructed 9×50 finder works exceptionally well, providing a left-right and up-down corrected image like a pair of binoculars and revealing fainter stars that are not visible to the naked eye, as well as many bright deep-sky objects. However, the finder’s crosshairs are challenging to see in the dark, and beginners may find it difficult to use to locate a target because it is not possible to view through it and up at the sky simultaneously. It takes practice to aim the tube and then check the target through the finder without overshooting it. If you find the 9×50 finder difficult to use, you may want to add a zero-power reflex sight or red dot finder to assist or replace it.
The StellaLyra 8” f/6 Dobsonian telescope is mounted as an alt-azimuth like all Dobsonians. The telescope moves vertically with the aid of two side bearings attached to the tube, and moves horizontally by rotating the top of the base against the bottom. Unlike other Dobsonians that use plastic bearings, the StellaLyra 8” f/6 Dobsonian uses bearings that are similar to those used in industrial machinery.
For side-to-side movement, the StellaLyra 8” f/6 Dobsonian uses roller bearings, which function similarly to a “lazy Susan,” with small plastic rollers between the telescope’s ground board and the bottom face of the rocker box. This system is affordable, smooth, and mostly effective, but it can be loose and spin easily on a windy night or cause overshooting when adjusting the telescope’s direction. Tightening the center bolt can also make the motions sticky and difficult to control. It is hard to achieve the exact level of friction required, which is why Dobsonians typically use Teflon bearings that glide against a laminate surface, such as the melamine that covers the StellaLyra Dobsonian base. Replacing the lazy Susan with furniture glides or PTFE (Teflon) pads is a simple and inexpensive solution.
The StellaLyra 8” f/6 Dobsonian’s altitude bearings are sealed ball bearings with large plastic knobs that adjust friction, affecting the telescope’s ease of movement. The bearings can be tightened to secure the telescope for storage or when swapping out heavy accessories which might otherwise cause it to suddenly move up or down due to being unbalanced. You can also slide them along the tube depending on where the telescope’s center of balance is with your usual accessory setup. It is best to set both bearings’ position indoors beforehand since adjusting them evenly in the field can be difficult.
The StellaLyra 8” f/6 Dobsonian’s base weighs approximately 12 kg due to its use of particle board instead of actual wood material, making it more dense and awkward to move than it may initially seem. The base arrives flat-packed and can be assembled quickly with the included screws and tools. However, frequent use can damage the particle board base, and humidity can cause it to deteriorate further, particularly if you live in a humid climate or mistreat it. In such cases, you can create a replacement using basic carpentry tools and plywood for increased durability. Replacing the stock particle board base with a lighter plywood one can also make it more manageable for users who may find the weight and size challenging to set up or use. Alternatively, placing the scope on a cart or dolly can also work.
Should I buy a Used StellaLyra 8″ f/6 Dobsonian?
A used StellaLyra 8″ f/6 Dobsonian could be a good choice, and a used unit will save you money which you can then use to purchase additional accessories. When considering the purchase of any used Dobsonian, be sure to inspect it for any damage to the mirror coatings or base. A damaged base can be replaced easily and inexpensively, and building your own base may provide additional benefits, as discussed earlier. However, damaged mirror coatings can be a bigger issue. If the mirror looks dull, it may simply require cleaning. But if there are signs of moss or chemical corrosion, pinholes, or a transparent appearance to the coating, the mirror may need to be recoated, which can be costly. Be sure to weigh the cost of recoating against the cost of buying a new telescope before making a decision.
Dents on the tube of a used Dobsonian should not be a major concern, as they are often unavoidable and usually do not affect the light path. If any dents are affecting the optics, they can often be removed using tools similar to those used for removing dents on a car, or even with a plunger or hammer in some cases.
The StellaLyra 8” f/6 Dobsonian is easily one of the best options for a telescope in its price range, much like its American sisters the Apertura AD8 and Zhumell Z8. However, there are some other scopes you may wish to consider.
- The Celestron StarSense Explorer 8” Dobsonian features Celestron’s StarSense Explorer technology to help you find objects in the night sky with a simple app and a bracket that attaches to your smartphone, allowing the utilization of its camera, GPS, and gyroscopes for accurate, real-time position information. It also features a lightweight base that’s easier to carry than the StellaLyra 8” f/6. However, few other features or accessories are included despite the high price of this scope.
- The Bresser Messier 8″ telescope offers comparable performance to the StellaLyra 8” f/6 and has a better mount, along with a nice Crayford focuser, but offers few other features or accessories and the included ones are shockingly poor in quality.
- The Ursa Major 8” Dobsonian is a simple 8” Dobsonian with the same optics as the StellaLyra 8” f/6, a pair of Plossl eyepieces, and a straight-through 9×50 finder. However, there are of course some corners cut to keep the price tag so low; this scope is prone to balance issues with heavier eyepieces and the focuser is only a single-speed design.
- The Sky-Watcher Virtuoso GTi 150P is a highly portable telescope with a fully motorised mount, featuring GoTo technology that can be controlled via a smartphone app or manually aimed by hand. Although its aperture is smaller than the StellaLyra 8” f/6 Dobsonian and it can only accept 1.25” eyepieces, its compact design makes it an excellent choice for those who prioritise portability and ease of use. The manual Heritage 150P is also a brilliant scope if you’re not concerned about losing computerised functionality.
- The StellaLyra 10” f/5 Dobsonian shares the exceptional features of its 8” counterpart, with the same focal length, features, and accessories but a 36% increase in light collecting power thanks to its larger aperture. It is only slightly heavier than the 8” f/6 model and not any longer, so if you can afford the 10” we would certainly recommend it.
- The Bresser Messier 10” Dobsonian boasts a smooth and sturdy mount, along with high-quality 10” optics and a decent reflex sight finder, making it a solid choice for those looking for a reliable telescope. However, it lacks some of the other useful accessories found in other models.
- The Explore Scientific 10” Ultra Light Dobsonian features a more compact design compared to solid-tubed Dobsonians like the StellaLyra Dobsonians, as well as compared to the Sky-Watcher FlexTube scopes, making it an excellent option for those looking for a more portable telescope. However, it requires more assembly and comes with fewer accessories than most of its competitors.
- The StellaLyra 12″ f/5 Dobsonian offers the same features, accessories and basic design as its 10” and 8” counterparts but with more than twice the light-collecting power of an 8” and 44% more than a 10” Dobsonian. However, it is rather heavy and awkward to carry around, while its tube is extremely large which can complicate storage. You might want to consider one of the collapsible or truss tube 12” Dobsonians instead if this is a concern.
- The Explore Scientific 12″ Ultra Light Dobsonian is an all-metal truss Dobsonian which breaks down into separate pieces for the most compact form factor possible, and has features like a dual-speed Crayford focuser and smooth, large altitude bearings to minimize balance issues. However, few accessories are included with this telescope, and assembly is more complicated with a truss tube design compared to a simpler solid or collapsible tubed instrument.
- The Sky-Watcher Skyliner 300P FlexTube’s FlexTube design isn’t the most well-accessorized or compact, but provides a compromise between the complex assembly and numerous separate parts of a truss tube and the challenges of accommodating a solid-tubed scope of this aperture.
- The Celestron StarSense Explorer 10” Dobsonian offers the same lightweight base and StarSense Explorer technology as the 8” version, but as with other 10” Dobsonians doesn’t take up much more space or weigh much more than its 8” counterpart. However, it is similarly lacking in accessories.
Aftermarket Accessory Recommendations
The StellaLyra 8” f/6 Dobsonian comes with a nice accessory package to get you started. Nonetheless, it’s certainly worth acquiring a few additional pieces of kit. A 7mm UWA eyepiece (171x) and/or a 4mm UWA (300x) will allow the StellaLyra 8” f/6 to achieve even higher magnifications than the StellaLyra’s provided 9mm Plossl ocular and the UWA design offers a huge, immersive 82-degree apparent field of view as well. A 16mm UWA (75x), or a 15mm redline/goldline eyepiece (80x) fits nicely between the provided 30mm and 9mm eyepieces for medium magnification as well. You’ll also want to pick up a good Cheshire collimation tool to ensure your StellaLyra Dobsonian provides the sharpest possible images at all ranges of magnification.
Additionally, some users may find aiming the StellaLyra 8″ f/6 and other Dobsonians with only a right-angle finder attached, such as the provided 9×50 correct-image unit, somewhat challenging, as it’s not exactly intuitive to coarsely aim without looking down the barrel of the telescope. Replacing it entirely or at least supplementing it with a Telrad is a common and highly recommended solution.
Finally, a narrowband Ultra High Contrast (UHC)/OIII nebula filter is an indispensable accessory that will significantly enhance your views of nebulae, such as the Orion Nebula, when employed with virtually any telescope capable of delivering respectable deep-sky views, like the StellaLyra 8″ f/6 Dobsonian. This filter also improves the visibility of planetary nebulae by reducing the perceived brightness of nearby stars, making it less difficult for you to discern the small planetary nebulae concealed among them at low magnification. Additionally, you will be able to detect the spectacular Veil Nebula and other faint objects with an appropriate nebula filter provided your sky conditions are otherwise reasonably dark.
What can you see?
The StellaLyra 8″ f/6 Dobsonian, like any quality telescope with an 8″ aperture, is a versatile instrument that can provide views of various celestial objects. Even in light-polluted areas, the telescope can reveal a diverse range of open star clusters such as M11 and M35, individual stars in globular clusters such as M13 and M15, as well as many double stars.
The quality of any telescope’s views of most deep-sky objects largely depends on the amount of light pollution in your area. Suburban light pollution can essentially wipe out galaxies altogether and significantly impair nebulae, while highly light-polluted skies will make viewing everything but star clusters a frustrating task. Moderately dark skies are necessary for optimal viewing of galaxies and nebulae with any telescope. Practice over time also helps.
The StellaLyra 8″ f/6 Dobsonian can show you hundreds of colorful open star clusters and a few dozen globular clusters, most of which can be resolved into individual stars with a high-magnification eyepiece. Nebulae such as the Orion Nebula (M42) are detailed and bright even under mediocre skies and are further enhanced by a UHC filter. The Veil Nebula is spectacular under dark skies with a UHC or Oxygen-III filter, and you can also go after quite a few colorful planetary nebulae. The StellaLyra 8″ f/6 Dobsonian can easily show all of the galaxies in the Messier catalogue, and you can start to pick out a few features in brighter and more detailed galaxies under optimal conditions. The spiral arms of M51 can be faintly glimpsed at medium magnification, while the dust lanes in M82, M64, and the enormous Andromeda Galaxy (M31) are strikingly evident thanks to their high contrast.
Additionally, the StellaLyra 8″ f/6 Dobsonian can offer superb views of Solar System objects, including the Moon’s numerous craters and mountain peaks, and the phases of Mercury and Venus. When observing Mars, the StellaLyra 8″ f/6 Dobsonian can reveal a few dark markings along with the planet’s polar ice caps and any dust storms, though you’ll have to wait for Mars to be favorably close to Earth to clearly resolve any of these surface features. Jupiter’s cloud belts, the Great Red Spot, and its four prominent moons are visible through the telescope. These moons appear as tiny disks alongside their jet-black shadows when they transit in front of Jupiter, causing an eclipse over the planet’s cloud tops.
Saturn’s rings and the Cassini Division within the rings, as well as some of the planet’s dull brownish cloud belts, are also easily visible with the StellaLyra 8″ f/6 Dobsonian. Under optimal conditions, up to seven of Saturn’s moons can be seen, though they only appear as star-like points. Uranus appears as a turquoise disk, and its four largest moons are technically visible in dark skies, although they are at the limit of what can be observed with an 8″ telescope and are best left to larger scopes. Neptune appears as a tiny blue dot, but its moon Triton shines fairly conspicuously next to it. It might be possible to observe Pluto, but it’s relatively faint, appearing as nothing more than a star-like point, and larger instruments are likely to be needed to bring it out as it continues to dim as it gets further away from the Sun.