The C401A3 gives you the complete CEM40 mount system without adding a hard travel case you may not need. It includes the CEM40 head with internal iPolar, the matched 1.75-inch stainless-steel LiteRoc tripod, one 5 kg (11 lb) counterweight, counterweight shaft, and Go2Nova hand controller.
The mount itself carries up to 40 lb (18 kg) of telescope and imaging equipment on a head weighing just 17.4 lb (7.9 kg). That combination gives you useful room for cameras, filter wheels, focusers, guiding equipment, and future changes to the telescope without turning the mount head into something difficult to move.
If your CEM40 will spend most of its time at home, move between the garage and backyard, or travel in storage you already own, the C401A3 gives you the important pieces without including the fitted hard case. If you want the same mount, tripod, and counterweight with iOptron's hard case for the head, choose the C402A3 package instead.
Key Features
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Complete CEM40 mount system. Includes the mount head, 1.75-inch LiteRoc tripod, 5 kg counterweight, internal iPolar, hand controller, and counterweight shaft.
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40 lb payload capacity. iOptron rates the CEM40 for up to 18 kg (40 lb) of telescope and imaging equipment, excluding counterweights.
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17.4 lb mount head. At 7.9 kg, the CEM40 provides substantial imaging capacity without requiring a heavy mount head.
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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.
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Internal iPolar electronic polar scope. Camera-based polar alignment is built directly into the RA axis.
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Periodic error below ±7.5 arcseconds. iOptron specifies native PE below ±7.5 arcseconds over the mount's 400-second worm period.
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Permanent Periodic Error Correction. A trained correction can be stored in the mount to reduce the repeating component of RA tracking error.
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Belt-driven worm system. Both axes use 110mm diameter, 216-tooth worm wheels driven by 17mm brass worms through synchronous belts.
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45mm steel axles and 68mm bearings. Substantial internal components for a mount head weighing less than 18 pounds.
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Precision stepper motors. 128 micro-steps provide a specified motor resolution of 0.08 arcsecond.
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Up to 4.5°/sec slewing. Maximum GoTo speed is approximately 1080× sidereal.
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Go2Nova hand controller. Provides an 8-line × 21-character display, built-in heater, and a database of more than 212,000 objects.
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Built-in GPS. Supplies 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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Power-down memory. Positional information can be retained following a normal power-down.
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Configurable meridian treatment. The mount can stop or flip, with settings allowing up to 10° of travel past the meridian when clearance permits.
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6-inch dual saddle. Accepts both Losmandy D and Vixen-style dovetail plates.
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Through-mount connections. A 12V DC output rated to 3A, ST-4 guide connection, and USB are routed through the mount.
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Optional Wi-Fi. iOptron's external iStarFi adapter can add wireless mount control.
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1.75-inch LiteRoc tripod included. Stainless-steel legs provide a portable support matched to the CEM40.
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5 kg counterweight included. One 11 lb counterweight is supplied for the 28mm stainless-steel counterweight shaft.
- Two-year limited warranty.
A CEM40 System Without the Hard Case
The difference between the C401A3 and C402A3 packages is straightforward. Both give you the CEM40 with internal iPolar, the 1.75-inch LiteRoc tripod, and one 5 kg counterweight. The C402A3 also includes iOptron's fitted hard case for the mount head.
If the mount normally moves from a garage or storage room to the same observing area outside, the case may not be important to you. The C401A3 lets you buy the mount, matched tripod, and counterweight together without making the case part of the package.
The LiteRoc's stainless-steel legs give the CEM40 a portable foundation sized for this mount family. The included 5 kg counterweight rides on a 28mm × 280mm stainless-steel shaft.
The exact amount of counterweight required depends on the complete telescope and imaging train. Some heavier or differently balanced systems may require another weight, but additional counterweight does not increase the mount's 40 lb payload rating.
40 Pounds of Capacity on a 17.4-Pound Head
The payload-to-head-weight ratio is one of the reasons the CEM40 has found such a useful place between smaller portable mounts and heavier equatorial systems.
An imaging payload is more than the optical tube. Cameras, filter wheels, electronic focusers, guide equipment, rotators, rings, dovetails, dew-control hardware, and cables all count toward the weight riding on the mount.
The CEM40 gives you up to 40 lb of rated capacity for that complete system while keeping the mount head itself at 17.4 lb.
Payload weight is not the only consideration. Tube length, diameter, center of gravity, wind exposure, focal length, and image scale all affect how demanding a telescope will be. A compact 25 lb system and a long 25 lb optical tube do not necessarily ask the same thing of the mount.
Tracking and Guiding
The standard CEM40 uses a conventional precision worm drive rather than a high-resolution tracking encoder.
Both RA and DEC use 110mm diameter, 216-tooth worm wheels driven by 17mm brass worms through synchronous belts. The RA worm completes one cycle every 400 seconds, and iOptron specifies native periodic error below ±7.5 arcseconds.
Permanent Periodic Error Correction allows the mount to store a correction for the repeating component of that RA worm error.
For demanding long-exposure astrophotography, particularly as focal length and image scale increase, conventional autoguiding remains the normal approach. PPEC handles the predictable repeating component while the guider can respond to movement in the complete telescope system.
If you want the same basic CEM40 platform with a high-resolution RA encoder and Real-Time Periodic Error Correction, the CEM40EC is the step up.
iPolar Built Into the RA Axis
The CEM40 includes iOptron's iPolar electronic polar scope inside the RA axis.
Rather than looking through a traditional optical polar scope and positioning a star on a reticle, iPolar photographs the surrounding polar sky and plate-solves the field. The software determines where the mount's RA axis is pointing relative to the celestial pole and shows you how to adjust the altitude and azimuth controls.
Polaris itself does not have to be visible. The camera still needs enough surrounding polar sky to identify the star field successfully, so iPolar cannot work through a building, tree, or other obstruction that blocks the entire area it needs to see.
For a mount that gets placed in the same backyard or patio location repeatedly, iPolar can make returning to an accurate polar alignment much simpler.
Connections for an Imaging System
The CEM40 includes a straightforward through-mount cable-management system.
A 12V DC output rated to 3A, an ST-4 guide connection, and USB are routed through the mount so those particular connections do not have to cross the moving axes externally.
This is a USB pass-through rather than a multi-port imaging hub. A system with several USB devices may still use a small hub or mini computer near the telescope.
The mount itself communicates with a computer through USB. Built-in Wi-Fi is not included, but iOptron's optional iStarFi adapter can add wireless mount communication.
What Owners Say on Cloudy Nights
Cloudy Nights owners repeatedly come back to the same things that make the CEM40 attractive on paper: useful capacity without a heavy mount head, convenient cable routing, and iPolar for a mount that is regularly set up and taken down.
"It's a powerhouse of a mount for its size."
That early CEM40 owner also singled out the through-mount USB, guide, and 12V connections as a useful part of the design and was particularly impressed with iPolar.
Other CEM40 owners describe the through-mount cabling, fit and finish, and relatively low weight as some of their favorite parts of the mount. For people who set up in the yard repeatedly, several owners have also described marking permanent tripod-foot locations so the mount returns close to polar alignment before iPolar makes the final adjustment.
That owner experience is more useful than assigning the CEM40 an unofficial imaging payload or promising a particular guiding RMS. The recurring story is that it offers a lot of imaging mount for its physical size and remains manageable enough to set up regularly.
Under the Night Sky
A backyard is exactly where the CEM40's combination of capacity and portability can make sense. It is substantial enough to become the center of a complete imaging system without requiring the mount to live permanently outdoors.
With a shorter refractor and a narrowband filter, suburban light pollution does not have to end the night. Large emission nebulae such as the Rosette, California, Heart and Soul, Veil, and North America Nebula can become multi-night projects collected from home.
Move to more focal length and smaller targets come into reach as well. The important part is that the mount has room for the complete imaging train while remaining light enough to carry back inside when the session is over.
Setup Tip for a Repeated Backyard Location
If you normally use the mount in the same place, mark the tripod-foot positions.
Three small pavers set flush with the lawn, discreet marks on a patio, or another repeatable reference can put the LiteRoc back in nearly the same orientation each night. Mark which leg faces north as well.
You will still verify and refine polar alignment with iPolar, but beginning from the same physical position can reduce how much adjustment is required and make repeated setup more consistent.
What's Included
- 1x iOptron CEM40 Center-Balanced Equatorial mount head
- 1x Internal iPolar electronic polar scope
- 1x 6-inch Losmandy D / Vixen dual saddle
- 1x Go2Nova hand controller with built-in heater
- 1x iOptron 1.75-inch LiteRoc stainless-steel tripod
- 1x 5 kg (11 lb) counterweight
- 1x 28mm × 280mm stainless-steel counterweight shaft
- 1x 100–240V AC adapter for indoor use
- Mount connection accessories
Hard case not included. The C402A3 package adds iOptron's fitted hard case for the mount head.
Frequently Asked Questions
What is the difference between the C401A3 and C402A3?
Both packages include the CEM40 with internal iPolar, the 1.75-inch LiteRoc tripod, and one 5 kg counterweight. The C402A3 also includes iOptron's fitted hard case for the mount head.
How much can the CEM40 carry?
iOptron rates the CEM40 for up to 40 lb (18 kg) of telescope and imaging equipment, excluding counterweights. Tube geometry, center of gravity, wind exposure, focal length, and image scale should also be considered when choosing a mount.
Should I limit an imaging payload to 30 pounds?
There is no separate official 30 lb imaging rating. iOptron publishes a 40 lb maximum payload, with the qualification that optical-tube size and length matter. A lighter payload generally gives a mount more operating margin, but there is no single reduced number that applies to every telescope.
Does the package include a tripod and counterweight?
Yes. It includes the matched 1.75-inch stainless-steel LiteRoc tripod and one 5 kg (11 lb) counterweight.
Does it include a hard case?
No. A hard case is optional with the C401A3. Choose the C402A3 package if you want the fitted hard case included.
Does the CEM40 include iPolar?
Yes. Internal iPolar is installed in the RA axis.
Does iPolar require Polaris to be visible?
No. Polaris itself does not have to be visible, but iPolar does require enough unobstructed surrounding polar sky to plate-solve successfully.
Does the CEM40 need guiding?
For demanding long-exposure astrophotography, especially at longer focal lengths, guiding is the normal approach. The standard CEM40 uses PPEC but does not have the high-resolution RA encoder of the CEM40EC.
CEM40 or CEM40EC?
Both share the same basic 40 lb mechanical platform. The standard CEM40 uses conventional worm tracking with Permanent Periodic Error Correction. The CEM40EC adds a high-resolution RA encoder with Real-Time Periodic Error Correction. If you expect to guide and do not specifically want encoder correction, the standard CEM40 gives you the same basic payload class for less.
Does the CEM40 have built-in Wi-Fi?
No. The mount communicates over USB. iOptron's optional iStarFi adapter can add wireless mount control.
Does it have a built-in USB hub?
No. USB is routed through the mount along with a 12V/3A output and ST-4 connection, but it is not a multi-port USB imaging hub.
Can I use a pier later?
Yes. The included LiteRoc can remain your portable support while an appropriate Tri-Pier or permanent pier is used for a more fixed installation.
Accessories
iOptron Hard Case for CEM40 (sold separately): useful if you later decide to transport or store the mount head in a fitted case.
iOptron 2.5 kg #8027-05 Counterweight (sold separately): useful when the complete telescope system requires more counterweight than the included 5 kg weight provides.
iOptron Tri-Pier #8034 (sold separately): a more substantial support option when portability is less important.
iOptron iStarFi Wi-Fi Adapter (sold separately): adds wireless mount communication.
Final Thoughts
The C401A3 makes sense when you want the CEM40 as a complete working mount system but do not need the fitted travel case.
You still get the pieces that matter every night: a 40 lb-capacity CEM40 head weighing 17.4 lb, internal iPolar, the matched 1.75-inch LiteRoc tripod, a 5 kg counterweight, PPEC, GPS, automatic zero search, and through-mount connections.
Cloudy Nights owners consistently point to the CEM40's relatively low weight, cable management, and easy polar-alignment system as some of the reasons it works well for repeated setup.
If the mount mostly moves between storage and your observing spot rather than spending its life on the road, the C401A3 gives you the CEM40 system you need and leaves the hard case out of the box.
