iOptron CEM120 — 52 kg centre-balanced observatory mount The iOptron CEM120 (#7300) is iOptron's observatory-class centre-balanced equatorial mount. At 26 kg, it carries payloads up to 52 kg excluding counterweights, ideal for large telescopes and complex imaging arrays on a permanent pier.
Manufacturer model: iOptron CEM120 (#7300) · Specifications checked against manufacturer data on 2026-11-03
The iOptron CEM120 (#7300) is iOptron's observatory-class centre-balanced equatorial mount. At 26 kg, it carries payloads up to 52 kg excluding counterweights, ideal for large telescopes and complex imaging arrays on a permanent pier.
Huge 216 mm, 360-tooth worm wheels on 80 mm steel axles and 125 mm bearings provide stability and smooth motion. iOptron specifies periodic error under ±3.5 arcseconds over the 240-second worm period, with permanent periodic error correction. Encoder-equipped CEM120EC/EC2 versions reach under 0.15 arcseconds RMS.
Along with RS232 and USB, the CEM120 adds built-in Wi-Fi and LAN for remote operation. An extensive cable-management system routes 12 V power, USB 2.0 and USB 3.0, ST-4 and AUX connections through the mount to prevent tangles. Precision altitude and azimuth adjusters have 0.5 arcminute and 3 arcminute divisions.
| Design | Centre-balanced equatorial (CEM) |
|---|---|
| Payload | 52 kg, excluding counterweight |
| Mount weight | 26 kg |
| Latitude range | 0–68° (0.5 arcmin divisions); low-latitude CW shaft below 10° |
| Azimuth adjustment | ±5° (3 arcmin divisions) |
| Periodic error | Under ±3.5 arcsec (encoder-measured, 240 s); PPEC |
| Worm gears | 216 mm, 360 teeth, zero backlash; 26 mm worm |
| Axes | 80 mm steel; 125 mm bearings |
| Resolution | 0.07 arcsec |
| Maximum slew | About 4°/s |
| Saddle | Losmandy D, 437 mm, spring-loaded |
| Counterweight shaft | 38 × 540 mm stainless steel, anti-slip |
| Counterweight | 10 kg |
| Mount base | 210 × 230 mm |
| Hand controller | Go2Nova 8410, 212,000+ objects |
|---|---|
| Polar scope | Optional iPolar |
| Ports | RS232, USB, LAN, Wi-Fi; ST-4; GPS |
| Cable management | 2 × DC 12 V (1 A), 2 × DC (5 A), ST-4, 2 × USB 2.0, 3 × USB 3.0, AUX |
| Meridian handling | Stop (0–14° past), automatic flip |
| Power | 12 V DC, 5 A; 100–240 V AC adapter included, indoor use only |
| Consumption | 0.7 A tracking; 1.8 A GoTo |
| Operating temperature | −10 to +40 °C |
| Pier | Optional |
iOptron CEM120 product page · CEM120 instruction manual
Standard CEM120 #7300 (PPEC), not CEM120EC/EC2 (encoder, <0.15 arcsec RMS). iPolar optional. Pier not included. Low-latitude CW (#7326LL) needed below 10 deg.
| Latitude range (°) | 0–68 |
|---|---|
| Azimuth adjustment (°) | ±5 |
| Periodic error | <±3.5 arcsec, PPEC |
| Worm period (s) | 240 |
| Axis shafts bearings | 80 mm steel; 125 mm bearings |
| Resolution (arcsec) | 0.07 |
| Max slew | ~4 deg/s |
| Cw shaft | 38 x 540 mm SS anti-slip |
| Counterweight (kg) | 10 |
| Mount base (mm) | 210 x 230 |
| Consumption | 0.7 A tracking; 1.8 A GoTo |
| Polar scope | Optional iPolar |
| Operating temperature (°C) | -10 to 40 |
Data sheet
Specific References
iOptron CEM120 — 52 kg centre-balanced observatory mount The iOptron CEM120 (#7300) is iOptron's observatory-class centre-balanced equatorial mount. At 26 kg, it carries payloads up to 52 kg excluding counterweights, ideal for large telescopes and complex imaging arrays on a permanent pier.
Manufacturer model: iOptron CEM120 (#7300) · Specifications checked against manufacturer data on 2026-11-03
