iOptron CEM120 Mount

CEM Design: A 115 lb Payload on a 57 lb Mount

The core of the CEM120's capability is its Center-Balanced Equatorial Mount architecture. By positioning the payload's center of gravity directly over the pier's central axis, the design delivers exceptional stability and allows for a significantly higher payload capacity relative to its own weight. This makes the 26 kg (57 lbs) all-metal mount head capable of securely handling large optical tubes up to 52 kg (115 lbs), making it an ideal platform for observatory-class instruments.

The mount features robust, easy-to-use gear clutches and precision altitude and azimuth adjustment systems for accurate polar alignment across a wide 0° to 68° latitude range. A standard Losmandy D-style saddle provides a secure, non-slip connection for your telescope's dovetail bar, ensuring rigidity throughout your imaging session.

Precision Drive System: 0.07 Arcsecond Resolution and PPEC

The CEM120's drive train is engineered for uncompromising astrophotography. Massive Φ216mm, 360-tooth zero-backlash worm wheels are paired with a precision stepper motor drive system with 128 micro-steps, resulting in a tracking resolution of just 0.07 arc seconds. This fine control allows the mount to execute precise GoTo slews and track celestial objects with the accuracy needed for long-exposure imaging.

Every CEM120 model includes Permanent Periodic Error Correction (PPEC) to minimize the worm gear's inherent tracking errors. For the most demanding applications, high-resolution encoder-equipped versions (CEM120EC and CEM120EC2) are available, which actively correct tracking in real-time to deliver a periodic error of less than ±3.5 arc seconds.

Integrated Cable Management: 10+ Ports for a Tangle-Free Setup

Cable drag and snagging are eliminated with the CEM120's advanced cable management system. A comprehensive array of ports is built directly into the mount saddle and central column, preventing wires from wrapping around the mount during slews. This through-the-mount routing is essential for reliable remote and automated observatory operation.

• Power Outputs: Two 12V/5A DC ports and two 12V/1A DC ports provide power for your camera, dew heaters, and other accessories right at the saddle plate.
• Data Ports: Three USB 3.0 ports and two USB 2.0 ports handle high-speed camera data and guide camera connections without external hubs.
• Control Ports: An ST-4 guiding port, an auxiliary port, and connections for the optional iPolar electronic polar scope are all integrated.

Go2Nova 8410 Controller: GPS, WiFi, and Remote Observatory Control

The CEM120 includes the Go2Nova® 8410 controller, a powerful hub for mount operation. A built-in 32-channel GPS automatically inputs the date, time, and location for a fast and accurate setup. The mount also features an automatic zero search function to find its home position, ensuring repeatable and reliable startup every time.

While the hand controller provides full access to all functions, the CEM120 is designed for modern computer control. With built-in WiFi and a dedicated LAN port, you can connect directly to the mount for full remote operation using your favorite planetarium software or automation programs like N.I.N.A. or Sequence Generator Pro, making it a perfect match for a backyard observatory.

iOptron CEM120 vs. Sky-Watcher EQ8-R Pro: Design and Connectivity

In the heavy-duty observatory class, the CEM120 is often compared to the Sky-Watcher EQ8-R Pro. While both mounts handle similar payloads, they achieve it with different design philosophies.

• Sky-Watcher EQ8-R Pro Advantage: The EQ8-R Pro features a belt-drive system, which can provide very smooth tracking with low backlash. It also includes Freedom-Find dual encoders as a standard feature across all models, allowing for manual slewing without losing alignment.
• iOptron CEM120 Advantage: The CEM120's primary advantage is its superior payload-to-weight ratio of 2:1, making its 57 lb head significantly lighter and more manageable than the EQ8-R Pro's ~63 lb head for a similar 115 lb capacity. More importantly, the CEM120's integrated cable management system is far more advanced, offering a complete solution for power and data that eliminates cable wrap—a critical feature for remote imaging that the EQ8-R does not have integrated to the same degree.