The iOptron HEM27 is built around a simple idea: a serious imaging mount should not have to be a serious burden to carry.
The mount head weighs just 8.15 lb (3.7 kg) with the saddle installed, yet iOptron rates it to carry 29.7 lb (13.5 kg) without a counterweight. Add the optional counterweight system and the published capacity rises to 44 lb (20 kg).
That combination makes the HEM27 especially attractive for portable astrophotography. A small-to-medium refractor, cooled camera, filter wheel, focuser, guider, and the rest of a normal imaging train can ride on a mount light enough to carry outside in one hand.
The HEM27 gets there with a hybrid drive system. Right ascension uses a strain-wave gear for high torque in a compact package, while declination uses a backlash-free worm-and-belt drive. The result is a mount designed around portability without abandoning the guiding and control features expected from a modern equatorial system.
Features
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29.7 lb counterweight-free payload. Carry up to 13.5 kg without a conventional counterweight shaft and stack of weights.
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Only 8.15 lb with the saddle installed. The payload-to-mount-weight ratio is approximately 3.65:1.
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Up to 44 lb with a counterweight. Add the optional shaft and counterweight when a heavier or more demanding telescope configuration calls for additional capacity.
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Hybrid drive system. The RA axis uses a strain-wave drive while DEC uses iOptron's backlash-free worm-and-belt system.
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360-second RA gear period. The standard HEM27 does not include a high-precision RA encoder, so long-exposure imagers should plan on guiding when their image scale requires it.
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Go2Nova 8409 hand controller included. Standalone GoTo control with an approximately 212,000-object database and nine slew speeds up to 6° per second.
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Built-in 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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Computer control. Use iOptron Commander and ASCOM on Windows or compatible third-party INDI software on other platforms.
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Integrated ST-4 autoguider port. Traditional guiding is supported in addition to software-based pulse guiding.
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Power and USB pass-through. The mount provides 12V accessory outputs and USB 2.0 pass-through to the saddle, helping keep camera and accessory cabling close to the telescope.
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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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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. The same saddle accepts either standard, although changing between them requires reconfiguring the saddle hardware.
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Soft carrying case included. Appropriate for a mount whose biggest advantage is how easily it travels.
Why iOptron Calls It a Hybrid
The HEM27 is not simply a smaller version of a conventional German equatorial mount, and it is not a dual-strain-wave mount either.
The right-ascension axis uses strain-wave gearing. That is the axis doing the continuous tracking work, and the compact, high-torque drive is what allows the mount to carry a substantial payload without requiring an equally substantial counterweight on the other side.
Declination takes a different approach. iOptron uses a worm-and-belt drive designed for backlash-free operation, with a gear switch that allows the DEC axis to be released for balancing.
No RA balancing is required. That is one of the biggest practical differences between setting up the HEM27 and setting up a traditional German equatorial mount.
29.7 Pounds Without a Counterweight
The headline payload number is 29.7 lb, but the geometry of the telescope matters along with the scale weight.
iOptron bases the rating on the payload's center of gravity being approximately 200mm from the RA rotation axis, or an optical tube roughly 220mm in diameter. A compact 25-pound imaging rig and a long 25-pound refractor do not put the same load on the drive.
That makes the HEM27 a particularly natural match for compact refractors and astrographs where the mass stays relatively close to the mount. Longer tubes, large rear-mounted imaging trains, and wind-sensitive telescopes deserve more margin below the published payload rating.
If the system needs more capacity, the optional counterweight shaft and weight increase the published rating to 44 lb.
This Version Does Not Include iPolar
The H272 is the standard HEM27 without iPolar. There is no conventional optical polar scope built into the mount either.
That is not necessarily a disadvantage if you already polar align through imaging software. SharpCap, NINA, ASIAIR, PHD2, and other software-based methods can all provide a practical path to polar alignment without looking through a polar scope.
If you prefer iOptron's electronic polar-alignment system, iPolar is also available for the HEM27. iOptron currently lists the HEM15, HEM27, and HEM44 among the supported mounts for its HEM-specific iPolar configuration.
The choice between this model and the iPolar-equipped HEM27 therefore comes down mostly to workflow. If you already use plate solving or another camera-based polar-alignment routine, the H272 lets you avoid paying for a second alignment system you may never use.
Built to Be Guided
The standard HEM27 does not have the high-precision RA encoder found in the HEM27EC.
For long-exposure deep-sky imaging, the sensible approach is to guide it. The mount provides an ST-4 autoguider port and also supports software-based guiding through compatible computer-control systems.
Strain-wave mounts can behave differently from conventional worm-drive mounts because the RA tracking rate can change more quickly through portions of the gear cycle. That often makes relatively frequent guide corrections useful, but there is no one exposure time or aggressiveness setting that belongs on every HEM27.
Seeing, guide-camera sensitivity, telescope focal length, image scale, and the rigidity of the tripod all affect the result. Tune the guider to the actual stars in your exposures rather than chasing somebody else's RMS number.
Clean Cabling at the Telescope
A portable mount loses some of its appeal if every setup involves rebuilding a nest of cables.
The HEM27 routes its main cabling internally and provides USB and 12V pass-through connections near the saddle. A camera or accessory can therefore use short cables at the telescope instead of having every connection hang across the moving axes.
iOptron provides two 12V outputs with a combined maximum of 4A along with USB 2.0 pass-through. The arrangement does not replace a full imaging power-management system for every rig, but it can substantially simplify a typical portable setup.
Go2Nova Control and Wi-Fi
The included Go2Nova 8409 hand controller gives the HEM27 standalone GoTo control with an approximately 212,000-object database and nine slew speeds up to 6° per second.
Wi-Fi is provided through the hand controller, so keep the handset connected when you want to control the mount wirelessly through iOptron Commander Lite, SkySafari, or another compatible system.
Computer control is also available through USB. Windows users can work through iOptron Commander and ASCOM, while third-party INDI support provides additional options on macOS, Linux, and Raspberry Pi systems.
From the Cloudy Nights Community
HEM27 owners on Cloudy Nights tend to come back to the same advantage: portability changes how often the mount actually gets used.
One longtime owner who also uses an HEQ5 described the HEM27's altitude and azimuth locking bolts as an annoyance, but considered them a small price to pay for a mount that could simply be picked up and carried outside instead of living on wheeled bars in the garage.
That complaint about the locking hardware is worth knowing before the first night out. The altitude and azimuth locks use socket-head hardware rather than large hand knobs, and some owners keep a T-handle hex wrench with the mount or replace the hardware with lever-style alternatives.
Owners also confirm that the saddle deserves a little explanation. It accepts both Vixen and Losmandy-D plates, but it is not a modern clamp that instantly accepts either size. Changing from its default Vixen configuration to Losmandy-D requires moving the fixed block and flipping the locking block.
Guiding reports are more useful than quoting one impressive RMS number. Standard non-EC HEM27 owners report successful multi-minute imaging when the mount is guided, but results vary with image scale, setup, seeing, and guiding configuration. That is the right expectation for this version: guide it well and let the low mount weight be the reason you chose it.
A Few Setup Details Worth Knowing
The HEM27 has two latitude ranges: 15–41° and 39–65°. Switching between them requires relocating the latitude position bolt and locking screws, so it is something to do at home rather than discovering after dark at a distant observing site.
The convertible saddle also ships in its Vixen configuration. If your telescope uses a Losmandy-D plate, convert the saddle before the first observing session and leave it configured for the dovetail standard you normally use.
With a longer refractor or a deep imaging train, a MiniPier can also be useful for keeping the camera and focuser clear of the tripod legs near the meridian and zenith.
What's Included
- iOptron HEM27 hybrid strain-wave equatorial mount head
- 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
- Soft EVA carrying case
Not included: tripod, counterweight shaft and counterweight, or iPolar electronic polar scope.
Frequently Asked Questions
How much can the HEM27 carry without a counterweight?
iOptron rates it for 29.7 lb (13.5 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 shaft and weight, iOptron raises the published payload rating to 44 lb (20 kg), subject to the same payload-geometry considerations.
Does this HEM27 include iPolar?
No. The H272 is the standard HEM27 without iPolar. The mount also does not include a conventional optical polar scope. You can polar align with compatible imaging software or add an appropriate iPolar configuration separately.
Can I add iPolar later?
Yes. iOptron currently lists the HEM27 as compatible with its HEM-specific iPolar configuration. Make sure you order the correct version for the HEM27.
Should I guide the standard HEM27?
For typical long-exposure deep-sky imaging, yes. The standard HEM27 does not include the high-precision RA encoder of the HEM27EC. The mount supports both ST-4 and software-based guiding.
Can it image unguided?
Short exposures at forgiving image scales may be possible, but this is not the version to buy specifically for long unguided imaging. If encoder-assisted unguided tracking is a major goal, the HEM27EC is the model designed around that capability.
Does it work with ASIAIR?
HEM27 owners use the mount successfully with ASIAIR systems, although connection methods have varied with firmware and ASIAIR revisions. Community reports include both Wi-Fi through the 8409 handset and connections using the handset as the communication path. Treat ASIAIR compatibility as a system-integration question rather than assuming every connection method behaves identically.
Does it work with NINA?
Yes. On Windows, the HEM27 can be controlled through iOptron Commander and ASCOM, allowing compatible applications such as NINA and PHD2 to communicate with the mount.
Is the saddle really Vixen and Losmandy compatible?
Yes, but it is convertible rather than instantly dual-width. The saddle ships configured for Vixen plates. Changing it to Losmandy-D requires repositioning and flipping parts of the saddle assembly.
What tripod fits it?
The HEM27 is compatible with iOptron's LiteRoc tripod for the CEM26/HEM27/GEM28/HAE29 family as well as compatible carbon-fiber tripod options. A matching MiniPier is useful when additional telescope-to-tripod clearance is needed.
What power does it require?
The mount uses 12V DC at up to 5A through a 5.5/2.5mm center-positive input. A 100–240V AC adapter for indoor use is included.
Final Thoughts
The HEM27 makes the most sense for an imager who is tired of carrying more mount than telescope.
At 8.15 lb with the saddle installed, it is light enough to carry outside without turning setup into a project, yet the 29.7 lb counterweight-free rating gives it room for a very capable portable imaging system.
The hybrid drive is part of what makes that possible: strain-wave gearing handles RA while the backlash-free worm-and-belt system handles DEC. The included 8409 controller provides standalone GoTo and Wi-Fi, saddle-mounted power and USB help clean up the imaging train, and the electronic brake and zero-position search take care of some of the details you would expect from a much heavier mount.
This H272 version is the one to choose if you already polar align with software and do not need iPolar built into the mount. Plan to guide it, keep the telescope geometry sensible, and the HEM27 gives you something that matters every clear night: a capable imaging mount that is easy enough to actually take outside.
