iOptron CEM40 Center Balanced GoTo Equatorial Mount with 1.5" Tripod and Hard Case
Part Number: C402A1
Serious Performance, Streamlined Setup — For Stargazers on the Move
The iOptron CEM40 is the perfect blend of portability and precision, designed for astronomers who want exceptional tracking performance and mount stability—without hauling 50 pounds of gear into the field. Whether you’re building a travel rig or simply want a high-capacity equatorial mount that’s easy to carry and fast to set up, the CEM40 delivers.
At just 15.8 pounds, the CNC-machined CEM40 mount head can support up to 40 pounds of gear (excluding counterweights), thanks to iOptron’s patented Center-Balanced Equatorial Mount (CEM) design. This configuration optimizes load distribution by placing the center of gravity directly over the tripod, minimizing torque on the drive system and allowing the motors to work more efficiently. The result? Less vibration, smoother tracking, and greater overall stability—especially under asymmetrical imaging payloads.
This version of the CEM40 comes with the 1.5" stainless steel tripod, a slightly lighter-weight tripod than the LiteRoc but still a solid performer for visual use and lighter imaging setups. And for added protection during transport, this configuration includes a custom hard case for the mount head, keeping your equipment safe during trips to star parties, remote dark-sky sites, or backyard observatories.
Alignment Without Guesswork: Built-In iPolar™
The included iPolar electronic polar alignment scope is fully integrated into the mount’s RA axis and aligned at the factory, meaning you’ll never need to collimate or recalibrate. Using onboard plate solving and a sensitive CMOS sensor, iPolar helps you achieve accurate polar alignment—even when Polaris is obstructed or invisible. Just connect the mount to your computer, launch the iPolar software, and follow the real-time guidance. No peering through tiny polar scopes, no neck strain, and no star hopping required.
For astrophotographers, this means better first-time GoTo accuracy, improved tracking, and fewer headaches during multi-hour imaging runs. For visual observers, it means more observing time and less setup time—especially in urban or tree-obstructed environments.
CNC Precision, Stepper Motors, and Zero Backlash Worm Gears
Inside the CEM40, you’ll find high-precision stepper motors mated to zero-backlash 216-tooth worm wheels on both the RA and DEC axes. The RA and DEC axles are made from hardened steel and supported by oversized 68mm ball bearings, ensuring smooth slewing and consistent tracking under heavy loads. These components are CNC-machined and anodized for strength, durability, and long-term thermal stability.
Out of the box, the CEM40 delivers a typical periodic error of ±7 arcseconds, which can be further refined with Permanent Periodic Error Correction (PPEC). For imagers seeking even tighter tracking, iOptron offers the CEM40EC variant, which adds a high-resolution RA encoder and real-time PEC (RPEC) correction down to <0.25 arcsec RMS. But even the standard CEM40 offers excellent long-exposure performance—especially when paired with autoguiding.
Sleek Control and Sky-Rich GoTo
The included Go2Nova® 8407+ hand controller is one of the most powerful (and underrated) tools in the astrophotography world. With an internal 359,000+ object database, including the full Messier, NGC, IC, UGC, and Caldwell catalogs, you’ll never run out of things to observe. Custom objects, star identification, pointing assist, and constellation tours are all built in.
The 8407+ features a clear, backlit 8-line LCD display and even includes a built-in heater to prevent fogging on cold nights. Navigation is intuitive, firmware is field-upgradable, and you can connect the mount to your PC via USB for remote operation or planetarium control. The maximum slew speed is 4.5° per second, ensuring you can cover wide areas of sky in moments—perfect for long-night imaging plans or showpiece visual tours.
Travel-Ready, Cable-Conscious, and Universally Compatible
This mount is designed to travel. The CEM40 head ships with a custom hard case—a rugged storage solution that protects your investment while in transit. The included 1.5" stainless steel tripod is lighter than the 1.75" LiteRoc or 2" iOptron tripods, making it easier to carry while still offering good stability for moderate payloads. For those needing even more rigidity, both LiteRoc and Tri-Pier options are available separately.
The integrated cable management system includes 12V power out, USB, and ST-4 ports—minimizing external cable runs and reducing the chance of snags during slewing. The patent-pending Universal Self-Centering Saddle (USCS) accepts both Vixen and Losmandy-style dovetails without the need for adapters, and it automatically centers and locks your OTA securely in place.
Finally, a 32-channel GPS receiver is built into the mount head for automatic time, date, and location syncing. Wi-Fi control is available via iOptron's optional external Wi-Fi module, allowing you to control the mount wirelessly using SkySafari or iOptron Commander.
Technical Specifications
Mount Type: Center-balanced German Equatorial (CEM)
Payload Capacity: 40 lbs (18 kg)
Mount Head Weight: 15.8 lbs (7.2 kg)
Payload-to-Weight Ratio: 2.5
Material: CNC-machined aluminum, steel axles
Exterior Finish: Red and black anodized
Latitude Range: 0°–60° (special shaft option for <10°)
Azimuth Adjustment: ±6°
RA/DEC Worm Gears: 216 teeth, Ø110 mm, zero backlash
Worm Diameter: 17 mm
RA/DEC Axles: Ø45 mm steel
Bearings: Ø68 mm
Motors: 1.8° stepper motors, 128 micro-steps
Motor Resolution: 0.08 arcseconds (200 pulses/sec)
Slew Speed: Up to 4.5°/second
Periodic Error: <±7 arcsec (typical)
PEC: PPEC (CEM40), RPEC (CEM40EC)
Polar Alignment: Internal iPolar electronic scope
Hand Controller: Go2Nova 8407+ with backlit LCD
Object Database: 359,000+ objects
Autoguiding: ST-4 compatible port
Communication: USB
Power Requirement: 12V DC, 5A
Power Consumption: 0.6A (tracking), 0.9A (GoTo)
GPS: Built-in 32-channel
Wi-Fi: Optional external adapter
Cable Ports: DC12V (3A), ST-4, USB
Tripod: 1.5" stainless steel
Counterweight: One 10 lb (4.5 kg) stainless steel
Hard Case: Included for mount head
Observing Tip
The 1.5" tripod included with this configuration is ideal for visual observers, DSLR astrophotographers, or anyone prioritizing portability over heavy-duty support. It's a great match for lighter OTA setups—like 4" to 5" refractors or 6" RCs—but if you plan to image with heavier rigs, consider upgrading to the 1.75" LiteRoc or 2" Tri-Pier for increased rigidity.
The included hard case also makes this an excellent choice for those who travel often or want to store their mount safely between uses without the bulk of foam-padded boxes.
Final Thoughts
The CEM40 with 1.5" tripod and case is an elegant solution for astronomers who need full-featured GoTo control, premium mechanics, and modern alignment tools in a mount that's light enough to take on the road. With a 40 lb payload, factory-integrated iPolar alignment, and rock-solid construction, it's a serious mount that performs well beyond its modest size.
If you're ready to step up from entry-level mounts or need a dependable field companion for visual or mid-weight imaging use, the CEM40 C402A1 delivers professional-grade performance without professional-level hassle.
