The CEM70EC2-NUC is built around a different idea from the other CEM70 models: instead of putting the imaging computer on the ground and running a bundle of cables up to the telescope, put the computer on the mount and let it travel with the imaging system.
The saddle includes a mounting platform for a compatible slim NUC-style mini PC less than 38mm thick. Power, Ethernet, and USB connections are routed through the mount, so the computer can sit beside the telescope while cameras, focusers, filter wheels, guide equipment, and other accessories connect close to where they are actually used.
Underneath that computer-ready connection system is iOptron's most sophisticated CEM70 tracking configuration: high-resolution encoders on both RA and DEC, with dual-axis Real-Time Periodic Error Correction. iOptron specifies encoder-corrected periodic error below 0.3 arcsecond RMS over the 348-second RA worm period.
The CEM70EC2-NUC still carries up to 70 lb (31.8 kg) of telescope and imaging equipment on a mount head weighing 30 lb (13.6 kg). It combines a serious imaging payload, dual encoder feedback, internal iPolar, on-mount computer integration, and through-mount cable management in a system that can still be transported in its included hard case.
Key Features
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70 lb payload capacity. iOptron rates the CEM70EC2-NUC for up to 31.8 kg (70 lb) of telescope and imaging equipment, excluding counterweights.
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30 lb mount head. A relatively manageable head for a mount in this payload class.
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Dual high-resolution encoders. High-precision positional feedback is provided on both the RA and DEC axes.
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Dual-axis Real-Time Periodic Error Correction. iOptron uses the encoder system for real-time correction rather than relying on a conventional trained PPEC curve.
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Encoder-corrected PE below 0.3 arcsecond RMS. iOptron specifies this measurement over the 348-second RA worm period under bench testing.
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NUC-ready saddle. Designed to accept a compatible slim NUC-style mini PC less than 38mm thick.
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Through-mount NUC connections. Power, Ethernet, and USB connections are routed between the RA axis and saddle so the computer can ride with the telescope.
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Internal iPolar electronic polar scope. The polar-alignment camera is built into the RA axis and uses plate solving rather than requiring you to position Polaris on a traditional reticle.
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Center-Balanced Equatorial design. iOptron's CEM layout places more of the combined mount and payload mass directly over the tripod or pier.
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151mm worm wheels on both axes. RA and DEC each use a 248-tooth worm wheel driven by a 21.2mm worm.
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55mm steel axles and 80mm bearings. Substantial mechanical components support the CEM70's larger payload class.
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Precision stepper motors. 128 micro-steps provide a specified motor resolution of 0.07 arcsecond.
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Up to 3.75°/sec slewing. Maximum GoTo speed is approximately 900× sidereal.
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Go2Nova 8410 hand controller. Includes an 8-line × 21-character display and built-in heater.
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Built-in 32-channel GPS. Supplies UTC time and location information to the mount.
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Automatic zero-position search. The mount can electronically locate its mechanical reference position.
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Configurable meridian treatment. The mount can stop or automatically flip, with settings allowing up to 10° of travel past the meridian when clearance permits.
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8-inch spring-loaded dual saddle. Accepts both Losmandy D and Vixen-style dovetail plates.
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Hard carrying case included. Protects the 30 lb mount head during storage and transport.
- Two-year limited warranty.
Put the Imaging Computer on the Mount
The NUC version is designed to solve one of the less glamorous problems in astrophotography: cables.
A complete imaging system may include a cooled camera, guide camera, filter wheel, electronic focuser, rotator, dew-control equipment, and several other USB and power connections. When the computer sits on a table or tripod below the mount, many of those cables have to bridge the moving RA and DEC axes.
The CEM70EC2-NUC moves the computer to the telescope side of that equation.
A compatible slim NUC-style computer mounts directly at the saddle. Cameras and accessories can plug into the computer and nearby mount connections, allowing most of the short equipment cables to move with the payload rather than hanging down toward a laptop on the ground.
That can make a complex imaging system considerably cleaner, particularly during large slews and meridian flips.
NUC Power, Ethernet, and USB
The mount provides dedicated cable paths for the on-mount computer, but it is important to understand what those connections do.
NUC power is pass-through. The mount does not internally convert its normal 12V supply into 19V for the computer. A dedicated NUC power input is located at the rear of the RA axis. The voltage supplied there is passed through the mount to the NUC power connection at the saddle.
Many traditional Intel NUCs use 19V, while some later mini PCs may use a different input voltage. Use the power supply and voltage required by the particular computer you install.
Ethernet is also pass-through. The LAN connection at the rear of the RA axis is routed to the saddle. Connect the rear LAN port to your network and the NUC can use that wired network connection without a separate Ethernet cable hanging across the mount.
USB connects the NUC to the mount's USB system. This allows the on-mount computer to communicate with the mount and compatible USB equipment through the integrated cable-management system.
These are cable-routing features rather than an internal computer, network switch, or power converter. The NUC itself and its required power source are sold separately.
Two High-Resolution Encoders
The EC2 designation means this version has high-resolution encoder feedback on both axes.
On the RA axis, the encoder allows the mount to continuously monitor and correct the repeating error produced by the worm-drive system. iOptron specifies encoder-corrected periodic error below 0.3 arcsecond RMS, measured on the bench over the 348-second worm period.
The second high-resolution encoder adds direct positional feedback on the declination axis rather than relying solely on commanded motor movement through the gear train.
iOptron describes the EC2 system as providing dual-axis Real-Time Periodic Error Correction.
That makes the EC2-NUC different from the standard CEM70EC, which has its high-resolution tracking encoder on RA only.
What the Encoders Do — and What They Don't
Encoder feedback improves the mount's knowledge and control of its own axes. It does not give the mount direct knowledge of every source of motion seen by the imaging camera.
Polar-alignment error, atmospheric refraction, seeing, wind, differential flexure, and movement elsewhere in the telescope system remain outside the encoder itself.
For demanding long-exposure astrophotography, particularly at long focal lengths and small image scales, guiding can therefore remain useful even on an EC2 mount.
The reason to choose the EC2 is not that it makes every other form of correction unnecessary. It is that the mount has high-resolution positional feedback on both axes and handles much more of its own tracking behavior internally.
Room for the Complete Imaging System
A 70 lb payload rating is most useful when you think about the complete imaging train rather than the bare optical tube.
A C11, large refractor, Ritchey-Chrétien, or similar telescope can gain substantial weight once you add rings, dovetails, a cooled camera, filter wheel, focuser, rotator, corrector, off-axis guider, dew equipment, cabling, and the on-mount computer itself.
The CEM70EC2-NUC gives those systems room to grow without moving into the much larger CEM120 class.
Payload weight is still only one part of mount selection. Tube length, diameter, center of gravity, wind exposure, focal length, and image scale all affect how demanding a telescope will be on the mount.
iPolar Built Into the RA Axis
The CEM70EC2-NUC includes iOptron's iPolar electronic polar scope inside the RA axis.
Instead of looking through a traditional optical polar scope, you connect the iPolar to a supported computer and let the software plate-solve the surrounding polar star field. It determines where the RA axis is pointing relative to the true celestial pole and then shows you how to adjust the mount's altitude and azimuth controls.
The pole star itself does not have to be visible. The camera still requires enough surrounding polar sky for its plate solve to succeed, but you do not have to identify Polaris or Sigma Octantis and place it on a reticle manually.
With a NUC installed on the mount, that same computer can become the control point for iPolar and the rest of the imaging software.
How You Control the NUC
The mount itself does not include built-in Wi-Fi on this version.
Your remote connection is to the computer riding on the saddle. If the NUC or mini PC has its own Wi-Fi, it can connect to your wireless network directly. For a wired connection, the CEM70EC2-NUC provides Ethernet pass-through from the rear of the RA axis to the saddle.
Once the computer is on your network, remote-desktop software can let you operate the imaging computer from another machine elsewhere on that network.
That distinction is important: it is the NUC or mini PC providing the remote-computing environment. The mount is providing the physical support and the cable paths that make an on-mount computer practical.
Through-Mount Accessory Connections
In addition to the dedicated NUC connections, the CEM70EC2-NUC provides cable management for the rest of the imaging train.
The system includes a mount-powered 12V output rated to 3A, additional DC pass-through connections with a combined capacity of up to 5A, an ST-4 guide connection, iOptron accessory connection, and USB 2.0 connectivity near the saddle.
As with the NUC power connection, some accessory-power connections are pass-through. Their output voltage depends on the voltage supplied to the corresponding input at the RA axis.
Always match the input voltage and available current to the actual requirements of the equipment being powered.
Transportable Without Being a Small Mount
The CEM70EC2-NUC weighs 30 lb without its counterweight. That is not grab-and-go, particularly once a large imaging system is assembled, but it remains very different from a CEM120-class installation.
The mount head can live on a permanent pier and still be removed when you want to take the system somewhere darker. An included hard case protects the head during storage and transportation, while the counterweight and support travel separately.
The on-mount computer concept can be useful here as well. Once the NUC has been configured with your imaging software, drivers, and equipment profiles, much of the control system can remain part of the mount rather than being rebuilt around a different laptop every time the system moves.
Tripod or Pier
The tripod or pier is sold separately.
iOptron lists the LiteRoc #8023ACC as a matched tripod for the CEM70 family. An appropriate Tri-Pier or permanent pier is also an option, particularly for heavier or permanent imaging systems.
With a mount capable of carrying 70 lb of telescope equipment, the support underneath it is part of the imaging system. Choose the tripod or pier for the complete installed telescope rather than the mount head alone.
Counterweights
The CEM70EC2-NUC includes one 20 lb (9.5 kg) counterweight and a 28mm × 415mm stainless-steel counterweight shaft.
One counterweight is sufficient for many moderate telescope configurations, but heavier systems can require additional counterweight to achieve proper RA balance. The amount needed depends on the complete payload and its center of gravity.
Additional compatible 28mm counterweights are sold separately.
What's Included
- 1x iOptron CEM70EC2-NUC Center-Balanced Equatorial mount head
- High-resolution encoders on RA and DEC
- Dual-axis Real-Time Periodic Error Correction
- 1x Internal iPolar electronic polar scope
- NUC mounting adapter
- Through-mount NUC power, Ethernet, and USB connections
- 1x 8-inch spring-loaded Losmandy D / Vixen dual saddle
- 1x Go2Nova 8410 hand controller with built-in heater
- 1x 28mm × 415mm stainless-steel counterweight shaft
- 1x 20 lb (9.5 kg) counterweight
- 1x Hard carrying case
- 1x 12V/5A AC adapter for indoor use
- Mount connection accessories
Not included: NUC or mini PC, NUC power supply, tripod or pier, additional counterweights.
Frequently Asked Questions
How much can the CEM70EC2-NUC carry?
iOptron rates the mount for up to 70 lb (31.8 kg) of telescope and imaging equipment, excluding counterweights. Telescope length, diameter, center of gravity, focal length, and imaging requirements should be considered along with total weight.
How much does the mount head weigh?
The CEM70EC2-NUC mount head weighs 30 lb (13.6 kg).
Is the NUC included?
No. The mount includes the NUC mounting adapter and through-mount connections, but the computer itself is sold separately.
What size NUC fits?
iOptron specifies a slim NUC-style computer less than 38mm thick. Because mini-PC dimensions and mounting arrangements vary, confirm physical compatibility before choosing the computer.
Does the mount power the NUC?
The mount provides a power pass-through path for the NUC. You supply the appropriate power at the NUC power input on the rear of the RA axis, and that power is routed to the saddle. The mount does not create 19V from its normal 12V mount supply.
Does it have Ethernet?
Yes, as a pass-through connection. Ethernet supplied to the LAN port at the rear of the RA axis is routed to the saddle for the on-mount computer.
Does the mount itself have Wi-Fi?
No. A NUC or mini PC with its own Wi-Fi can connect wirelessly to your network, or you can use the mount's Ethernet pass-through for a wired network connection.
What is the periodic-error specification?
iOptron specifies encoder-corrected periodic error below 0.3 arcsecond RMS, measured on the bench over the 348-second RA worm period.
Does it have encoders on both axes?
Yes. The CEM70EC2-NUC has high-resolution encoder feedback on both RA and DEC. iOptron describes the system as providing dual-axis Real-Time Periodic Error Correction.
Can I image unguided?
The dual encoder system can make unguided operation more practical in some combinations of focal length, exposure time, image scale, and polar alignment, but it does not correct every source of image motion. For demanding long-exposure imaging, particularly at longer focal lengths, guiding can remain useful.
Does it include iPolar?
Yes. iOptron's internal iPolar electronic polar scope is installed in the RA axis.
Does iPolar require Polaris to be visible?
No. Polaris itself does not have to be visible. Enough surrounding polar sky still needs to be available for the camera to plate-solve successfully.
CEM70EC versus CEM70EC2-NUC — what's the difference?
The CEM70EC has a high-resolution encoder on RA. The CEM70EC2-NUC adds a second high-resolution encoder on DEC and integrates mounting, power pass-through, Ethernet, and USB connections for an on-mount NUC-style computer.
Why put the computer on the mount?
It lets the imaging equipment connect to a nearby computer with short cables that move with the telescope. Only the necessary power and network connections need to reach the moving system, reducing the number of long cables crossing the mount's axes.
How many counterweights are included?
One 20 lb (9.5 kg) counterweight is included. Heavier telescope systems may require one or more additional counterweights.
What tripod should I use?
iOptron lists the LiteRoc #8023ACC as a matched tripod for the CEM70 family. An appropriate Tri-Pier or permanent pier is also an option for heavier or permanent installations.
Final Thoughts
The CEM70EC2-NUC is not simply a CEM70 with another accessory bolted to it. It is designed around the idea that the mount, telescope, cameras, and imaging computer can travel as one integrated system.
Dual high-resolution encoders give the mount direct positional feedback on both axes, while the NUC-ready saddle puts the control computer beside the equipment it operates. Power, Ethernet, USB, and accessory connections are routed through the mount instead of requiring a collection of long cables to cross the moving axes.
Underneath it all is still the useful CEM70 formula: a 70 lb payload on a 30 lb head, internal iPolar, GPS, automatic zero search, a substantial dual saddle, and an included hard case.
If you want dual encoder feedback and an imaging computer that can become part of the mount rather than another box sitting beside it, that is the reason to choose the CEM70EC2-NUC.
