
iOptron GEM28 Go-To German Equatorial Mount With iPolar, Hard Case, And Literoc Tripod
Manufacturer Part # G282A3
Manufacturer Part # G282A3
The iOptron GEM28 G282A3 mount package delivers serious performance in a travel-ready footprint. Combining the versatility of a precision German equatorial mount with the convenience of modern GoTo technology, this system includes the GEM28 mount head, iPolar™ electronic polar scope, LiteRoc stainless steel tripod, and a fitted hard case for safe transport and storage.
Designed for both visual astronomers and astrophotographers, the GEM28 supports a full 28-pound (12.7 kg) instrument payload while keeping the mount head weight to just 10 pounds (4.5 kg)—giving it one of the best capacity-to-weight ratios in its class.
With a broad latitude range of 10° to 70°, the GEM28 is a true world traveler. From Chile to Canada, it’s ready for action. The mount is CNC-machined and cast for strength without excess weight, and the interior mechanics feature brass worm gears, 30mm RA and DEC shafts, and spring-loaded gearing for consistent meshing and minimized backlash.
An integrated bubble level, large altitude adjustment screw, and twin azimuth knobs make alignment a breeze—especially when paired with the onboard iPolar electronic polar scope, which works even when Polaris is obscured.
The GEM28 features a synchronous belt transmission in both axes, turning against 144-tooth, 88mm drive gears. The result is whisper-quiet motion with minimal backlash—ideal for imaging and community outreach alike. Combined with dual-axis stepper motors and encoders, the mount achieves 0.17 arcsecond per step resolution, enabling buttery-smooth visual tracking and pinpoint star images during long exposures.
You’ll find multiple tracking rates to suit any target: sidereal, solar, lunar, King, and a user-defined rate. User-adjustable backlash compensation is included to fine-tune guiding accuracy.
Nine speed settings let you shift from ultra-fine guiding to quick slewing:
Guiding: Sidereal and 2x sidereal
Centering: 8x, 16x, 64x, 128x
Slewing: 256x (1°/sec), 512x (2°/sec), and up to 4°/sec
The included GoToNova® 8409 controller is more than just a handpad—it’s your gateway to over 212,000 celestial objects. Its large 8-line display with LED backlighting is easy to read at night, and the controller is internally heated to maintain full visibility and operation down to -20°C (4°F).
Catalog highlights include:
Messier, NGC, IC, UGC, MCG, Caldwell, Abell, Herschel
Comets, asteroids, double stars, named stars, variable stars
88 constellations and 60 user-defined objects
Whether you're hopping to showpiece nebulae or digging deep into the Abell catalog, the GEM28 has your sky covered.
The G282A3 mount provides several modern and legacy connection options:
Built-in Wi-Fi (via the hand controller) for wireless operation
USB port for firmware updates or PC control (ASCOM and INDI compatible)
ST-4 autoguider port for plug-and-play compatibility with common guide cameras
HBX ports for auxiliary accessories or optional GPS
You can expand your system with the optional iOptron iGuider autoguiding system (#3360) or 32-channel GPS module for automatic time and location sync.
The included LiteRoc tripod features 1.75" stainless steel legs and a die-cast spreader/accessory tray, offering excellent rigidity with surprisingly low weight. It supports the full mount and payload with confidence, and dampens vibrations quickly—critical when shooting long-exposure images.
The hard case is custom-fit for the GEM28 mount head and accessories, keeping your gear protected whether you're storing it at home or heading to a dark sky site.
To accommodate a wide range of optical tube assemblies, the GEM28 includes:
10 lb (4.5 kg) counterweight
8" x 20mm counterweight shaft
The mount accepts Vixen-style dovetail plates, compatible with most small to mid-sized OTAs. While it’s rated for a full 28-pound payload, imaging users will get the best performance with payloads in the 15–20 pound range, ensuring quicker damping and tighter star shapes.
When imaging with a refractor or compact OTA, take full advantage of the GEM28’s high mount-to-payload weight ratio. Keeping your gear comfortably under the limit improves tracking, reduces settling time, and helps the iPolar system work more effectively. A lighter, stiffer load almost always delivers better stars.
The iOptron GEM28 G282A3 package is a complete, compact observatory-in-a-box. You get the time-tested German equatorial format, intelligent GoTo capability, modern belt-driven motion, the iPolar alignment system, a robust stainless steel tripod, and a rugged travel case—all in a package that’s light enough to carry, but strong enough to support real imaging gear.
Whether you’re a backyard astronomer looking to level up your setup or a travel-hardened imager needing a reliable mount for the road, the GEM28 G282A3 checks all the boxes.
Mount | German Equatorial Mount |
Payload * | 28 lbs (12.7kg), exclude counterweight |
Mount weight | 10 lbs (4.5kg) |
Payload/Mount weight | 2.80 |
Structure Material | All metal, Casting + CNC machined |
Exterior Finish | Powder coating |
Periodic error (PE) ** | <±10 arcsec |
PEC | Yes, Permanent PEC |
Worm period | 600 sec |
Right Ascension worm wheel | Φ88mm, 144 teeth aluminum |
Declination worm wheel | Φ88mm, 144 teeth aluminum |
Right Ascension axis shaft | Φ35mm steel |
Declination axis shaft | Φ35mm steel |
Right Ascension bearing | Φ55mm ball bearing |
Declination bearing | Φ55mm ball bearing |
Worm gears | Φ15.2mm, Brass |
Motor drive | 1.8º stepper motor, 128X microdivision |
Resolution | 0.17 arc seconds |
Transmission | Synchronous belt |
Latitude adjustment range | 10º ~ 70º |
Azimuth adjustment range | ± 6º |
Polar Scope | iPolar Electronic polar scope |
Level indicator | Level bubble |
Hand Controller | Go2Nova® 8409 with ~212,000 objects database |
Tracking | Automatic |
Slew speed | 1×,2×,8×,16×,64×,128×,256×,512×,MAX(6º/sec) |
Power consumption | 0.6A(Tracking), 0.9A(GOTO) |
Power requirement | 12V DC, 5A |
AC adapter | 100V ~ 240V (included) |
Power-down memory | Yes |
Wi-Fi | Built-in |
Communication port | Yes (Wi-Fi and USB) |
Autoguide port | Yes (ST-4 compatible) |
Firmware upgrade | Yes |
PC computer control | Yes (ASCOM) |
Counterweight shaft | Φ20X200mm (M16), Stainless Steel |
Shaft extension | Φ20X120mm (M16), Stainless Steel |
Counterweight | 10 lbs (4.5kg) |
Tripod | 1.75" Stainless Steel (5kg) |
Dovetail saddle | 3.8" Vixen-style, center adjustable |
Carrying case | Optional |
GPS | Optional external 32-channel GPS |
Autoguiding | Optional external iGuider 1 |
Operation temperature | -10ºC ~ 40ºC |
Warranty | Two year limited |
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