iOptron CEM40EC Center Balanced GoTo Equatorial Mount with LiteRoc Tripod – Precision Tracking in a Lightweight Observatory-Grade Mount
A sub-arcsecond tracking mount for serious astrophotographers and visual observers who need performance without the weight.
The iOptron CEM40EC redefines what a portable equatorial mount can do. With a center-balanced architecture, a built-in high-resolution encoder on the RA axis, and a true sub-arcsecond RMS tracking accuracy (< 0.25 arcsec), this mount is a perfect solution for demanding astrophotographers who want observatory-class performance in a highly portable package.
Engineered from the inside out to deliver smooth, precise motion and intelligent automation features, the CEM40EC makes no compromises on quality. It includes the rugged 1.75" LiteRoc stainless steel tripod for enhanced field stability, and supports up to 40 pounds of payload while weighing just 15.8 pounds—a rare and welcome ratio for those who travel with their gear.
Center Balanced Design That Works for You
The heart of the CEM40EC is iOptron’s patented Center-Balanced Equatorial Mount (CEM) design, which shifts the payload directly over the tripod’s center of gravity. This optimized geometry enhances stability, reduces torque on the drive system, and improves performance when imaging at longer focal lengths.
Unlike traditional German equatorial mounts that rely heavily on counterweights for balance, the CEM40EC’s centerline design allows for a cleaner balance with less weight, making it ideal for remote setups, dark sky trips, and observatories alike.
Sub-Arcsecond Real-Time Tracking with RA Encoder
The “EC” in CEM40EC stands for Encoder Controlled, and that’s where this mount truly excels. A high-resolution encoder built into the RA axis allows for Real-Time Periodic Error Correction (RPEC) without requiring any user calibration. This means the mount corrects tracking errors on the fly as they occur—no training, no stored curves, and no delay.
In the field, this translates to unguided imaging for many deep-sky targets, and dramatically reduced guiding corrections when using an autoguider. It’s especially powerful for imagers running long focal length refractors, RCs, or heavy astrographs where tracking precision is mission-critical.
Field-Ready Features That Matter
iOptron has packed the CEM40EC with features designed to enhance both usability and accuracy:
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The iPolar™ internal electronic polar scope eliminates guesswork and allows you to align even when Polaris is obscured.
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The Universal Self-Centering Saddle (USCS) automatically centers Losmandy or Vixen dovetails for secure and repeatable mounting.
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A Go2Nova® 8407+ hand controller provides fast access to over 359,000 celestial objects, plus onboard star identification, GPS time sync, and automated routines.
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The internal cable management system prevents snagged wires and includes DC power, ST-4, and USB passthrough ports to streamline your setup.
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Optional Wi-Fi control is available via the iOptron iStarFi adapter for smartphone or tablet operation.
Mount Specifications and Capabilities
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Mount type: Center-Balanced German Equatorial Mount (CEM)
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RA Encoder: High-resolution encoder with real-time PEC (RPEC)
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Payload Capacity: 40 lbs (18 kg)
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Mount Head Weight: 15.8 lbs (7.2 kg)
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Gear System: 110mm diameter worm wheels, 216 teeth, 17mm worm
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RA/DEC Shaft: 45mm steel with 68mm bearings
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Periodic Error: < 0.25 arcsec RMS (EC version)
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Motor System: 1.8° stepper motors with 128 microsteps and 0.08 arcsec resolution
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GoTo Speed: Up to 4.5°/sec
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Autoguiding: ST-4 port and USB for ASCOM control
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Database: 359,000+ objects
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Power: 12VDC, 5A with included 100–240V AC adapter
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Operation range: –10°C to 40°C
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Included Tripod: 1.75" LiteRoc stainless steel with locking spreader
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Hard Case: Included for mount head
Supplied Accessories – What’s in the Box?
The CEM40EC (#C404A3) includes the precision-machined mount head, Go2Nova 8407+ hand controller, internal iPolar polar alignment system, 32-channel GPS module, 1.75" LiteRoc stainless steel tripod, 11 lb (5 kg) counterweight, stainless steel counterweight shaft, USB and RS232 communication cables, AC power adapter, and a custom-fitted hard case for the mount head. Everything you need for imaging and visual work—except your scope.
Observing Tip:
For long focal length astrophotography, the CEM40EC’s sub-arcsecond encoder tracking shines brightest. You can confidently run 5–10 minute exposures with minimal guiding correction—and in some cases, even unguided. Make sure your balance is dialed in, and the mount will do the rest.
Final Thoughts:
If you're looking for precision, portability, and proven reliability, the CEM40EC with LiteRoc tripod is one of the finest equatorial mounts in its weight class. It’s light enough to travel, accurate enough for professional-grade imaging, and flexible enough to grow with your astrophotography ambitions. Whether you're capturing galaxies under a dark sky or remotely running an observatory, this mount has the brains, brawn, and balance to keep you locked on target all night long.
