The Optical Tube
The Apertura AD12 is a 12” (305mm) f/4.9 Newtonian reflector on a Dobsonian mount with the same optical/mechanical configuration as all of the other Apertura Dobsonians.
At the AD12’s fast focal ratio of f/4.9, I could notice coma with low-magnification eyepieces like the included 30mm SuperView eyepiece. An aftermarket coma corrector and high-quality wide-angle 2” eyepieces will fix this problem, but be prepared to shell out big bucks for each. In any case, the maximum field of view that can be practically achieved with the AD12 and a 2” eyepiece is about 1.6°, or just over three times the angular diameter of the moon in the sky.
Unlike the smaller Dobsonians, the AD12’s mirror is thin enough that it needs a serious floatation mirror cell. The primary mirror sits on three triangles, each with three points to distribute the mirror’s weight so it does not sag and produce a blurred image.
Collimating AD12 is the same process for me as with the other Apertura AD Dobs, using 3 spring-loaded knobs. The ubiquitous 3 useless locking bolts are there, which I’d recommend be removed from the telescope before they crack the primary mirror or cause problems.
The AD12’s primary mirror is BK7 glass, which takes a fair amount of time to cool down to ambient temperature if brought outdoors from a warm indoor setting. Just like in the smaller Apertura Dobsonians, a battery-powered cooling fan is there to alleviate this. But I still spend a fair amount of time waiting for the mirror to acclimate and to get sharp views. This doesn’t mean I can’t use the telescope right away; I can. Just keep in mind that I don’t throw 400x at Uranus to look for its moons immediately after bringing the telescope outside.
AD12’s Adequate for the Price Focuser
The AD12 comes with a 2″ Crayford focuser that is the same as the dual-speed Crayford that Taiwan-based GSO makes and sells with their own lines and with different third-party rebrandings of their Ritchey-Chretien, Cassegrain, imaging Newtonian, and, of course, Dobsonian telescopes. The 10:1 reduction knob of this Crayford focuser allows for extremely fine focusing, which is particularly helpful when using very high magnifications with the AD12.
The standard GSO 2” dual-speed focuser on the AD12 is adequate for most eyepieces, but it can sag or have backlash under very heavy loads, such as a heavy 2” eyepiece inserted into a coma corrector. For example, my 21mm Ethos eyepiece plus a Paracorr corrector make it next to impossible to make adjustments with the fine focus knob accurately.
You may need to swap the AD12’s focuser for an aftermarket unit if you frequently use such accessories. However, I find it to be still a much better focuser than the cheaper single-speed units offered by competing manufacturer Synta under the Sky-Watcher and Celestron branded Dobsonians.
Optical Tube’s Portability
With it’s 1.5-meter (58”) long tube, minivans, SUVs, and even small pickup trucks can’t accommodate the tube sitting sideways across the back, and the tube is too fat to get away with putting it diagonal.
Thus, most vehicles will require you to put a seat down for the tube alone, which is at the very least a moderate inconvenience. The tube also weighs 48 pounds (about 22 kg), which is not easy to lift, especially for a wide, slippery metal tube. Lifting straps or a dolly would be a good idea.
Apertura AD12 Accessories
RECOMMENDED BUY FOR THE COMPLEMENTARY ACCESSORIES
The Apertura AD12 dobsonian telescope comes with two eyepieces: a 2” 30mm focal length “SuperView” (50x) and a 1.25” 9mm Plossl ocular (167x). To aim the AD12, you get a 9×50 Right Angle Correct Image (RACI) finderscope, the same as included with the AD8 and AD10. There is also a laser collimator included and a 1.25” “Moon filter” that screws onto 1.25” eyepieces, such as the provided 9mm Plossl.Buy Apertura AD12 from HighPoint
A Nice Finderscope
The AD12’s 9×50 finderscope does what it’s supposed to do. I could see much fainter stars than with my naked eye by a few magnitudes, along with bright deep-sky objects, even when light pollution washed them out to the naked eye.
But it’s not the best for beginners. You can’t see the crosshairs very well in the dark, and using it requires dead-reckoning by sighting down the tube and then looking through the finder. It’s easy to get lost or overshoot your target.
A zero-power reflex sight like a Telrad or red dot finder is a better choice for a beginner and also complements the 9×50 nicely.
The Lackluster Laser Collimator
The laser collimator included with the Apertura AD Dobs is one of the selling points of these telescopes and advertises itself as a high-quality solution that will save you money on aftermarket collimation tools. In actuality, it’s a poorly-made generic item that can be purchased for less than $30 on Amazon.
The generic laser that Apertura provides is not only poorly designed and completely lacking in quality control, but many of these lasers also ship with beam that are is concentric with the barrel.
Unless you enjoy taking the time to turn some tiny hex screws with the whole laser in a V-block, it will simply give you a completely inaccurate perception of how well your telescope is collimated and might hurt more than it helps your collimation. Your laser could appear completely aligned when your collimation is, in fact, quite askew.
In a pinch, you can collimate with just your eyepieces and a star. Check out our collimation guide for more information.
The Fair Set Of Eyepieces
The 30mm SuperView eyepiece provided with the AD series Dobsonians is a simple 5-element Erfle ocular with a roughly 70-degree apparent field of view, translating to a true field of 1.4° with the AD12.
The Erfle design does not do well in a faster f/5 telescope like the AD12, and a substantial portion of the field of view suffers from field curvature and astigmatism. This can be distracting, especially when viewing open star clusters or other large objects with bright spots at the periphery. Nonetheless, this century-old optical configuration works a lot better than a 25mm or 32mm 1.25” Plossl eyepieces, which most other manufacturers would bundle with a telescope like the AD12.
The GSO-made 9mm Plossl that comes with the AD12 and other Apertura Dobsonians is a 1.25″ unit. It has an apparent field of view of around 45°, though it’s advertised as a bit wider. This translates to a 0.27° or so true field of view with the AD12, or about half the moon’s apparent diameter—rather cramped.
This eyepiece also lacks any eye relief whatsoever, requiring you to jam your eyeball up to the glass (and deal with the various discomforts that will result).
Thankfully, it’s fairly sharp, and 167x is ideal for viewing the moon, planets, and globular clusters with this scope. However, I’d recommend replacing it with a 9mm “goldline” or “redline” eyepiece at the least, or preferably an ultra-wide-angle eyepiece designed with the AD12’s fairly fast focal ratio in mind.
The Unnecessary Moon Filter
The AD12’s included 1.25” “Moon filter” is not only almost completely unnecessary and, of course, not usable with the provided 2” low-power eyepiece, which it would theoretically be best with. Furthermore, it’s extremely low in quality, tinting the view green and adding a bit of fuzziness to boot. You’re best off discarding it.
AD12’s Dobsonian Mount
The AD12’s Dobsonian mount is of the same basic design as the other Apertura AD Dobsonians. It’s made almost entirely out of particle board and swivels left to right (in azimuth) on plastic roller bearings, much like a “lazy Susan”.
Unfortunately, this system doesn’t scale up too well with the weight and size of the AD12, and the scope is either too easy to swivel (often spinning in the wind) or too tight and jerky to adjust at high magnifications. Thankfully, you can buy aftermarket Teflon pads (or cut the sheet material yourself) for a fairly reasonable price to convert them to pivot like a standard Dobsonian. The bottom of the base is already covered in melamine, which produces the perfect “stiction” movements on Teflon pads.
For altitude (up/down) motion, the AD12 uses ball bearings to pivot, which actually work quite well even at high magnifications.These bearings have adjustable clutch knobs to loosen or tighten their movement, and you can slide the bearings along slotted tracks on the AD12’s tube to compensate for heavy accessories at the front or back.
Extreme amounts of weight on the front from accessories will still require you to add counterweights to the back of the scope or make a new, redesigned mounting. But for most 2” eyepieces and coma correctors with the stock finder or a lighter one such as a Telrad, you won’t have issues.
The bearings need to be perfectly parallel with one another (and thus locked in place) to slide into the rather tight notches on the AD12’s base. This process can be a little tricky to get right. I’d recommend practicing assembling the AD12 indoors under well-lit conditions before bringing it out to a star party.
The AD12’s base is heavy at 38 lbs (17 kg). It feels even heavier than the tube due to its awkward size and the density of the particle board. I’d definitely recommend putting it on wheels if you can, or replacing it with a lighter-weight plywood aftermarket or homemade base.
Worthiness of AD12 Kit Accessories
High Point offers a 2” Apertura 2x ED Barlow Lens 2x as a paid add-on on their AD12 web page. This Barlow works quite well, though you may not need a 2” Barlow lens at all. Our buyers’ guide to Barlow lenses goes into more detail and offers some alternative recommendations as well as a closer look at the 2” High Point/GSO 2x ED Barlow Lens.
The “12″ Dobsonian Performance Upgrade Kit” also offered by High Point for the AD12, is certainly worth the price, containing flocking to improve the blackening inside the tube and better collimation springs for the primary to retain collimation without the lock knobs. However, I’d say that the secondary mirror thumb screws are a debatable necessity.
Should I buy a used Apertura AD12?
A used Apertura AD12 dobsonian can be a great scope if you find one. They often go for substantial discounts used, since it’s next to impossible to ship one yourself at a reasonable cost, and not everyone can accommodate one of these mammoth instruments.
However, as with any used reflector, you should be wary of the condition of the AD12’s primary and secondary mirror coatings; recoating is possible but can get expensive.
A damaged base can be easily replaced if you have any woodworking skills, or you can order one from High Point or a third-party vendor.
Any dents in the tube can either be repaired or simply ignored, as they’re unlikely to intrude on the optical path of the telescope.
The Apertura AD12 offers some of the best value and performance in its price range alongside its twin, the Zhumell Z12. However, a 12” solid-tubed Dobsonian can be a bit intimidating for some, especially beginners, and you may want to opt for a smaller or otherwise more portable scope such as a 10” Dob or a truss tube 12”.
- Manual Scope: The Apertura AD10/Zhumell Z10/Orion SkyLine 10 offers the same great features and accessories as the AD12 but in a more compact form factor that’s easier to fit in a vehicle and carry around, as well as at a lower price. It is still fairly capable and hardly any heavier or bigger than the 8” version.
- Manual Truss Tube Scope: The Explore Scientific 10″ Hybrid Dobsonian is extremely compact thanks to its truss tube design and features easy collimation adjustments for the primary mirror. However, it is severely lacking in accessories and needs upgrades before you can begin actually using it.
- Partially Computerized 12″ Truss Tube Scope: The Orion SkyQuest XX12i Dobsonian is a great choice for anyone who wants a compact and weight-optimized 12” Dobsonian, featuring IntelliScope encoders to help you find deep-sky objects and a decent set of included features and accessories. Its truss tube collapses for transport, making it much easier to bring to dark skies than the AD12.
- Partially Computerized 12″ Scope: Celestron’s StarSense Explorer 12” Dobsonian lacks many of the niceties of the AD12, such as a dual-speed focuser, fan, or much in the way of an accessory kit. However, it features a lightweight Dobsonian base, built-in handles, and Celestron’s StarSense Explorer technology to help you navigate the night sky with your smartphone. The view at the eyepiece of either of these telescopes will be identical; the real question you need to ask yourself is whether it’s worth paying the premium for the StarSense Explorer technology and shelling out extra for a set of eyepieces and perhaps a focuser upgrade.
- Manual 12″ Truss Tube Scope: The Explore Scientific 12″ Truss Tube Dobsonian has a high-quality dual-speed Crayford focuser, an optimized all-metal structure that takes up very little space when disassembled, and silky-smooth manual movements. However, it includes no useful eyepieces or finder and also needs other add-ons like a shroud to work well.
- Manual 12″ Truss Tube Scope: The Sky-Watcher 12” FlexTube Collapsible Dobsonian is slightly more compact than the AD12, though it is not much lighter and the included accessories are fairly sub-par. However, the FlexTube design is simple to assemble and may be sufficient if you just need to cram the scope into a car and don’t mind its design/accessory concessions.
- Fully Computerized 10″ Truss Tube Scope: The GoTo Dobsonian Sky-Watcher 10” FlexTube Collapsible is a great choice if a fully automated system is desired, offering motorized GoTo and tracking capabilities in an easy-to-transport form factor slightly more compact than a regular 10” Dob. It is able to be aimed manually as well, thanks to the scope’s FreedomFind encoder system.
- Fully Computerized Tripod-Mounted Scope: The Celestron NexStar Evolution 8 provides full motorized tracking and pointing capabilities controlled over WiFi and is extremely compact thanks to its Schmidt-Cassegrain optical design and built-in lithium battery, perfect for those looking for a more portable telescope. However, it is not nearly as capable as a larger 10” or 12” Dob and its long focal length constricts its field of view somewhat.
Aftermarket Accessory Recommendations
The AD12 is a rather expensive scope, so don’t be afraid to skimp on accessories for it. A zero-power reflex sight, Telrad, Rigel Quikfinder, or Quinsight, for starters, will greatly assist in aiming the AD12. You can use the reflex sight by itself to aim at bright targets or use it to get in a general area where you think your target is and home in with the 9×50 RACI.
For higher magnification eyepieces, you could get a 6mm gold-line (250x) and/or a 4.5mm Astromania (333x with the AD12), but the AD12 works best with fancier eyepieces. We particularly like the Baader Hyperion and Explore Scientific 82-degree series, both of which come in a variety of focal lengths for low, medium, and high magnifications. We’d recommend something in the 5-7mm range, something in the 11-14mm range, and something in the 16-25mm range at the minimum for a good range of magnifications that can be used on a wide variety of targets.
You might also want a coma corrector such as the Explore Scientific HRCC or Tele-Vue Paracorr II – yes, they’re pricey, but you’ll be rewarded with truly sharp stars all the way to the edge of the field of view.
A nebula filter like the Orion UltraBlock 2” UHC will enable you to see emission nebulae more easily under light-polluted skies and will help boost contrast even under dark skies, but is not a replacement for them and does not work on non-nebula targets like star clusters and galaxies. It’ll work with both 1.25” and 2” eyepieces thanks to the threaded 2” to 1.25” adapter provided with the AD12.
What can you see with Apertura AD12?
With the Apertura AD12 dobsonian telescope, you can see many deep-sky objects that people with smaller scopes can only dream about.
Within the solar system, atmospheric turbulence—what is termed “seeing”—is the primary limitation when it comes to what you can see with the Apertura AD12. You can easily see the phases of Venus and Mercury, and the Moon will show amazing detail on almost any night. AD12 will show Mars with some of its dark spots, its ice caps, and any dust storms when it’s close to Earth, with the best apparitions occurring once every couple of years. Careful observing techniques may even manage to reveal its tiny asteroid moons, Phobos and Deimos, though they are quite tough to spot.
You can see Jupiter’s cloud belts magnificently with the AD12 on a steady night, and you’ll be able to easily see the Great Red Spot. The giant planet’s moons are tiny disks that can transit the planet with their shadows following behind, and on a perfect night, you can just barely spot a brown spot on Ganymede known as Galileo Regio, named for the astronomer who discovered the moons.
Through my observations, the AD12 has shown me a surprising amount of detail on and around the outer gas giants, too. Saturn’s rings are visible, as is the Cassini Division within them, and on a really good night, so is the Encke gap. You can also see quite a few cloud bands on Saturn itself and a blue-gray polar region where the planet’s hexagonal polar storms lurk. A half dozen or so of Saturn’s moons are visible, with Titan visibly larger than a point source and sporting a gold-yellow hue.
Uranus and Neptune are no longer mere fuzzy stars in AD12, but worlds in their own right with visible moons. Uranus’ greenish disk may sport very slight cloud markings, and its 4 brightest moons, Ariel, Umbriel, Oberon, and Titania, are faintly visible. Neptune is around half the angular size of Uranus and much fainter, but it is clearly a bluish disk, and its largest moon, Triton, can be seen more easily than the moons of Uranus, thanks to its larger size and more reflective surface.
Through the AD12 telescope, Pluto is also visible, though it’s currently stuck in a crowded neighborhood of stars in Sagittarius for the foreseeable future and will be hard to identify individually. Ceres, the closest dwarf planet, and Vesta, the second-largest asteroid, are easier to catch with the AD12. They are both easily seen in the 9×50 RACI and look like tiny, non-stellar gold dots. On the best nights, Vesta has a very slight oblong shape.
Outside the Solar System, the AD12 dobsonian can show a lot, but the best views require a clear and dark night sky away from city lights, which is why we stress that you make sure you can easily and safely transport this mammoth telescope. If you can’t see the Milky Way when you look up, the AD12 will certainly disappoint on galaxies, and the views of most other deep-sky objects will be greatly diminished by light pollution.
The AD12 will have no problem resolving even the tougher globular clusters. Thanks to its large aperture, the AD12 can also show you the spiral arms and dust lanes of dozens of the brightest galaxies—and reveal thousands upon thousands more, assuming you have good skies. M51’s spiral arms are clearly visible, as are the H-II regions that dot the spiral arms of M33. The Andromeda Galaxy, M31, takes up several fields of view. You can see an open cluster called NGC 206 inside it, as well as a small globular cluster called G1 a few degrees away (though you can’t see it without a much bigger telescope).
You’ll also be able to spot thousands of open star clusters with the AD12 dobsonian, many of which have colorful stars, dust lanes, or are embedded in larger nebulae or clusters themselves. They look magnificent, even from the city skies. They range from compact, almost globular-like clusters like M11 and M35 to looser clumps like the Pleiades (which also has a faint reflection nebula surrounding it that can be seen with the AD12 under dark skies).
The AD12 also reveals dozens of planetary nebulae, many of which have interesting colors and intricate details. These are so bright that they’ll look great even under suburban and city skies. Planetary nebulae range from the huge, bluish Dumbbell and Ring to the tiny, emerald-green Cat’s Eye. Some, like the Blinking Planetary Nebula, have white dwarfs in the middle that are easy to see, while others do not.
Emission nebulae like Orion and the Lagoon look stunning with the AD12, especially with dark skies and a UHC filter, and on a perfect night, you can just barely glimpse the famous Pillars of Creation within the Eagle Nebula, M16.
Transporting & Setting Up The AD12: Important Notes
The AD12’s optical tube is large (at 14” across and 58” long) and heavy (at about 48 pounds), so some consideration must be taken in moving it. Unlike with 8” and 10” instruments, the AD12’s tube will not fit across the back seat of most cars; you’ll need to fold down a seat unless you have a truck or van. Picking it up can also be problematic, as the painted metal tube is slippery and there are few points to grab. Setting the scope in the base is also hard because you can’t grab the bearings without hurting your fingers when putting the scope together, and they have to be moved very carefully into their slots. Obtaining lifting straps or moving the scope on a cart or dolly is a good idea if you have to move it frequently by yourself.
The particle board rocker box/base of the AD12 weighs in at 38 pounds. This doesn’t sound that bad, but you have to spread your arms out and carry it at an awkward angle, and it’s quite dense. Carrying it a long distance may cause you to tire or injure yourself. Making or buying a replacement plywood base, or simply putting the scope on wheels, might be a good idea.
High Point Scientific also advertises a dolly for the AD12, which works quite well and can be kept under the telescope while in use. However, this additional height may require you to bring out a stepladder or stool for shorter people to look through the eyepiece when the telescope is aimed higher in the sky.
AD12 or AD10/8? Is the AD12 too big?
Many people rightfully wonder (and you certainly will after reading our review) if the AD10 or AD8 is better for them as a first-time telescope. The answer really depends on your living situation. If you cannot get to dark skies often or at all, then transportation is more or less irrelevant, and you should go for the biggest telescope you can afford and house – which for many could be the AD12. If this is the case—or, inversely, if you already have a decent sky at your location—then whether or not it is easy to get the AD12 in and out of your home/garage is the primary consideration. If you have the ability (or requirement) to travel to a different location for viewing, then whether the AD12 fits in your vehicle and fulfills the aforementioned storage requirements is all that matters.
All in all, if you can physically house and move around the AD12, it’s hard to argue against one. Sure, the maximum field of view is a little smaller and the scope takes a bit longer to cool down compared to its smaller counterparts, but this is a negligible compromise compared to the improvement in brightness and clarity that comes from the AD12’s larger aperture.
I lived in a second-story apartment with a 12” Dobsonian similar in form factor to the AD12 under a Bortle 6 (that is, fairly bad) sky for a few months. It didn’t deter me from using it one bit. I carried the scope and base down the steps, strapped them to a hand truck, and rolled them to my car. However, I had a car big enough to fit the scope, dolly, and plenty of other stuff in, which may not be the case for everybody.