The iOptron HEM44 with iPolar is for the imager who has outgrown a small travel mount but does not want to go back to hauling a heavy equatorial head, a counterweight shaft, and a stack of weights every time the sky clears.
The mount head weighs just 13.65 lb (6.2 kg) with the saddle installed, yet iOptron rates it to carry 44 lb (20 kg) without a counterweight. Add the optional counterweight system and the published capacity rises to 55 lb (25 kg).
This H442A version adds iOptron's iPolar electronic polar scope directly to the mount. Instead of looking through a conventional polar-scope reticle, iPolar uses a camera and plate-solving software to show you how to adjust the mount toward the celestial pole. Polaris itself does not have to be visible, and the same system works in the Southern Hemisphere without requiring you to identify Sigma Octantis.
Underneath it is iOptron's hybrid drive system: strain-wave gearing on right ascension for high torque and counterweight-free operation, paired with a backlash-free worm-and-belt drive on declination. The result is a mount designed to carry substantially larger imaging systems while remaining practical to transport and set up.
Features
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44 lb counterweight-free payload. Carry up to 20 kg (44 lb) without a conventional counterweight shaft and stack of weights.
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Only 13.65 lb with the saddle installed. A payload-to-mount-weight ratio of approximately 3.2:1.
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Up to 55 lb with a counterweight. Add the optional shaft and 10 lb counterweight when a heavier or more demanding telescope configuration calls for additional capacity.
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Built-in iPolar electronic polar scope. A camera in the mount plate solves the polar-region star field and provides on-screen guidance for adjusting altitude and azimuth.
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Approximately 30-arcsecond polar-alignment precision. iOptron specifies maximum iPolar alignment accuracy at approximately 30 arcseconds.
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Polaris does not have to be visible. iPolar solves the surrounding star field rather than requiring the Pole Star itself to appear in the image.
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Hybrid drive system. Right ascension uses a 640:1 strain-wave drive while declination uses iOptron's backlash-free worm-and-belt system.
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270-second RA gear period. The standard HEM44 does not include the high-precision encoder of the HEM44EC, so demanding long-exposure imaging should normally be guided.
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Go2Nova 8409 hand controller included. Standalone GoTo operation with an approximately 212,000-object database.
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Wi-Fi through the hand controller. The 8409 provides wireless connectivity for compatible applications such as iOptron Commander Lite and SkySafari.
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Integrated ST-4 autoguider port. Traditional autoguiding is supported in addition to software-based pulse guiding.
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Through-mount cable management. Two 12V accessory connections and USB 2.0 pass-through help keep camera and accessory wiring away from the moving axes.
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Electronic friction brake. Designed to stop the mount safely during a planned or unexpected interruption in power.
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Power-down position memory. The mount retains its position through an interruption in power so operation can resume without starting the setup process from the beginning.
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Automatic zero-position search. Built-in sensing allows the mount to locate its reference position electronically.
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Vixen/Losmandy-D convertible saddle. Accepts either common dovetail standard.
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Equatorial operation. The HEM44 is a dedicated EQ mount designed primarily around tracking and astrophotography.
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Aluminum carrying case included. A fitted case protects the mount during transport.
iPolar Is the Difference
The standard H442 HEM44 has no polar scope. The H442A adds iPolar directly to the mount.
Instead of kneeling behind an optical reticle and trying to place Polaris at a calculated position, iPolar photographs the sky around the celestial pole and plate solves the field. The software determines where the mount's right-ascension axis is pointing relative to the true celestial pole and shows you how to correct it.
You make the altitude and azimuth adjustments while watching the result on screen. When the mount-axis indicator and celestial-pole indicator coincide, the alignment is complete.
Polaris itself does not have to be visible. Enough of the surrounding polar-region sky still needs to be available for the camera to successfully plate solve, but the alignment does not depend on seeing one particular star.
The same principle applies in the Southern Hemisphere, where Sigma Octantis itself does not have to be identified.
Approximately 30-Arcsecond Polar Alignment
iOptron specifies maximum iPolar alignment precision at approximately 30 arcseconds.
That is far more accuracy than is required simply for GoTo pointing. For astrophotography, however, good polar alignment reduces declination drift, helps limit field rotation, and reduces unnecessary work for the guider over a long imaging session.
Polar alignment and tracking accuracy are two separate things. iPolar accurately aligns the mount's RA axis with the celestial pole; it does not remove the periodic tracking error of the strain-wave drive.
The standard HEM44 has no high-precision RA encoder, so long-exposure deep-sky imaging should still normally be guided.
Why iOptron Calls It a Hybrid
The HEM44 is neither a conventional German equatorial mount nor a dual-strain-wave design.
Right ascension uses strain-wave gearing. That is where the ability to operate with a heavily unbalanced load eliminates the need for the traditional counterweight system and gives the HEM44 its unusually high payload-to-mount-weight ratio.
Declination uses a different solution: a belt-driven worm system that iOptron describes as backlash-free. Because the telescope can be moved forward or backward in the saddle to balance DEC, another strain-wave drive is not necessary on that axis.
The worm-drive DEC architecture also provides a path through the mount for stationary cable management.
The result is not strain-wave gearing everywhere. It is a hybrid design that uses each drive type where iOptron believes its advantages make the most sense.
44 Pounds Without Counterweights
The HEM44's defining number is 44 pounds.
That gives it considerably more room than a smaller travel mount for larger refractors, SCTs, astrographs, dual-scope systems, and imaging trains carrying cameras, filter wheels, focusers, guiders, rotators, and other accessories.
There is an important qualification to the payload rating. iOptron bases it on the payload's center of gravity being approximately 200mm from the RA rotation axis, or an optical tube around 220mm in diameter.
A compact 35-pound SCT and a long 35-pound refractor therefore do not place the same mechanical load on the mount. Tube length, diameter, rear-mounted imaging equipment, and wind exposure all matter along with scale weight.
The optional counterweight system raises the published payload to 55 lb, but a counterweight may also be useful with certain long or mechanically demanding telescope configurations below that limit.
Counterweight-free is a capability, not an obligation.
Guiding the Standard HEM44
The standard HEM44 does not have the high-precision RA encoder found in the HEM44EC.
iOptron does not publish a fixed periodic-error specification for the non-encoder HEM44. The company notes that strain-wave periodic error varies with payload, telescope position, and imbalance, so a single PE number is less useful than it would be for a conventional worm-drive mount.
For long-exposure deep-sky imaging, plan on guiding.
Because the tracking rate of a strain-wave drive can change relatively quickly through portions of its cycle, non-encoder strain-wave mounts often benefit from relatively frequent guide corrections. The correct guide exposure still depends on seeing, guide-camera sensitivity, focal length, image scale, and the rest of the system.
PHD2's Predictive PEC algorithm can also be useful because the HEM44's strain-wave drive has a repeating 270-second gear period. Give the guider time to learn the system before drawing conclusions from the first few minutes of a session.
And judge the final result from the actual subframes. Round stars matter more than producing the smallest possible number on a guiding graph.
From the Cloudy Nights Community
HEM44 owners on Cloudy Nights provide useful real-world context for both the mount's payload and its guiding behavior.
One owner using the standard HEM44 with a dual imaging rig measured unusually large raw periodic error in his particular setup. Despite that, he reported that PHD2's Predictive PEC learned the curve quickly and produced strong guided performance when seeing supported it.
That individual measurement should not be treated as the HEM44's periodic-error specification. iOptron specifically does not publish a fixed PE value for the standard mount because the behavior varies with load, position, and imbalance.
Another owner offers a useful HEM27-versus-HEM44 comparison. His roughly 30-pound 130mm triplet imaging system produced RA streaking on the smaller HEM27. Moving to the HEM44 solved the issue for his setup.
That does not create a universal weight cutoff between the two mounts. What it illustrates is the importance of telescope geometry. A long refractor with a substantial imaging train can become demanding well before the scale reaches a mount's advertised maximum payload.
The larger HEM44 platform gives those kinds of systems more mechanical margin while still avoiding the weight and counterweight burden of a traditional mount in the same general payload class.
Power-Down Memory
The HEM44 includes a particularly useful feature for a mount carrying a substantial imaging system: power-down position memory.
If power is interrupted, the mount retains its RA and DEC position. Once power returns, it can resume a GoTo slew or continue tracking without requiring you to start the alignment and positioning process from the beginning.
That does not mean every imaging application or camera sequence automatically resumes after a power failure. It means the mount itself retains where it was pointed.
The electronic friction brake works alongside that feature by stopping mount motion safely rather than allowing an unbalanced payload to swing freely if power disappears.
No GPS — Make Sure Time and Site Are Correct
The HEM44 does not contain its own GPS receiver.
The GoTo system therefore needs accurate date, time, UTC offset, longitude, latitude, and hemisphere information. Those values can be entered through the hand controller or supplied through compatible computer or mobile control software.
The mount should also begin from a correctly registered Zero Position. Its built-in zero-position search makes that straightforward, and Sync to Target can be used after centering an object to improve local pointing.
If the mount consistently points to the wrong part of the sky, check the time, UTC offset, longitude East/West setting, hemisphere, and Zero Position before assuming there is a mechanical problem.
Go2Nova Control and Connectivity
The included Go2Nova 8409 hand controller provides standalone GoTo control with an approximately 212,000-object database.
The handset also provides Wi-Fi for compatible mobile control through iOptron Commander Lite, SkySafari, and other supported applications.
Computer control is available through USB as well. Windows users can work through iOptron Commander and ASCOM, while compatible third-party INDI drivers provide additional options on macOS, Linux, and Raspberry Pi systems.
The mount includes an ST-4-compatible autoguider port for traditional guiding in addition to software-based pulse guiding through compatible computer-control systems.
What's Included
- iOptron HEM44 hybrid strain-wave equatorial mount head
- Factory-installed iPolar electronic polar scope
- Vixen/Losmandy-D convertible dovetail saddle
- Go2Nova 8409 hand controller
- 6P6C coiled hand-controller cable
- 12V/5A AC adapter for indoor use
- USB cable for mount control
- Mini-USB cable for iPolar
- Aluminum carrying case
Not included: tripod, counterweight shaft, or counterweight.
Frequently Asked Questions
What is the difference between this HEM44 and the standard HEM44?
The H442A includes iOptron's iPolar electronic polar scope built into the mount. The H442 uses the same basic hybrid drive and has the same payload capacity but does not include a polar scope.
How much can the HEM44 carry without a counterweight?
iOptron rates it for 44 lb (20 kg) without a counterweight. The rating assumes the payload center of gravity is approximately 200mm from the RA axis, so telescope geometry matters along with total weight.
How much can it carry with a counterweight?
With the optional counterweight system, iOptron recommends a maximum payload of 55 lb (25 kg) with a 10 lb counterweight.
Do I need to see Polaris to use iPolar?
No. iPolar plate solves the surrounding polar-region star field, so Polaris itself does not have to be visible. Enough of the surrounding sky still has to be visible for the camera and software to identify the field.
How accurately can iPolar align the mount?
iOptron specifies maximum alignment precision of approximately 30 arcseconds.
Does iPolar require a computer?
Yes. iOptron's official iPolar software runs on 64-bit Windows. The iPolar camera connects by USB during alignment. Once polar alignment is complete, that computer connection is not required simply for normal mount tracking.
Does iPolar replace guiding?
No. iPolar handles polar alignment. Guiding corrects tracking errors while an exposure is being made. They solve two different problems.
Should I guide the standard HEM44?
For typical long-exposure deep-sky imaging, yes. This model does not include the high-precision RA encoder found in the HEM44EC.
What is the periodic error of the HEM44?
iOptron does not publish a fixed periodic-error specification for the standard HEM44. The company says strain-wave PE varies with payload, telescope position, and imbalance. Treat the standard HEM44 as a guided imaging platform rather than buying it based on a particular unguided PE number.
What is the difference between the HEM44 and HEM44EC?
The HEM44EC adds a high-precision encoder to the right-ascension axis with Real-Time Periodic Error Correction. That substantially reduces the raw RA tracking error and can allow a different guiding strategy or, with appropriate systems, encoder-assisted unguided imaging.
What is the difference between the HEM27 and HEM44?
The two mounts share the same basic hybrid concept: strain-wave RA and worm/belt DEC. The HEM44 increases counterweight-free capacity from 29.7 lb to 44 lb and provides more mechanical margin for longer, heavier, and more heavily accessorized imaging systems. Telescope geometry matters as much as the number on the scale.
What is the difference between the HEM44 and HAE43?
Both offer similar published counterweight-free capacity. The HEM44 uses strain-wave gearing on RA and a worm/belt DEC drive and operates as an equatorial mount. The HAE43 uses strain-wave gearing on both axes and can operate in either equatorial or Alt-Az mode.
Does the HEM44 have GPS?
No. Time and site information must be entered manually or supplied through compatible control software.
Does the HEM44 work with ASIAIR?
HEM44 owners use the mount with ASIAIR systems, but driver selections and connection methods can change as third-party software evolves. We would treat ASIAIR as third-party integration rather than promise a particular driver selection indefinitely.
What tripod fits it?
The HEM44 mounts to compatible iOptron CEM40/GEM45/HAE43/HEM44 support systems, including the matched LiteRoc tripod and Tri-Pier. A compatible MiniPier can provide additional telescope-to-tripod clearance for long refractors and deep rear-mounted imaging trains.
What power does it require?
The mount uses 12V DC at up to 5A through a 5.5/2.5mm center-positive input. The included 100–240V AC adapter is intended for indoor use.
Final Thoughts
The HEM44 with iPolar solves two practical problems that tend to appear as an imaging system grows.
First, the 13.65-pound mount head carries up to 44 pounds without requiring the counterweight system normally associated with a telescope in this class.
Second, the built-in iPolar replaces a conventional polar-scope reticle with camera-based plate solving and on-screen adjustment guidance.
The standard HEM44 still needs guiding for demanding long-exposure imaging, and iPolar still requires a computer during alignment. But if that already matches the way you work, the combination is straightforward: carry less equipment outside, get the polar axis aligned accurately, connect the guider, and start imaging.
If your telescope has outgrown the HEM27 and you want iPolar built into the larger HEM44 from the start, the H442A is the version that puts those pieces together.
