iOptron HEM27EC Hybrid Strain Wave Drive with RA Encoder and Soft Case
iOptron has revolutionized the equatorial mount! The iOptron HEM27EC is an equatorial hybrid strain wave drive mount that is unparalleled in its weight-to-payload efficiency. Weighing only 8.15 lbs. (7.49 lbs. without the dovetail saddle), this mount head has a payload capacity of 29.74 lbs.! You don’t even need a counterweight or shaft to reach that impressive weight to payload capacity ratio. In order to make this vision a reality, iOptron utilized strain wave drive technology for the right ascension (RA) movement in tandem with a conventional, lightweight declination (DEC) worm drive. This is the premier mount for astrophotographers looking for a portable, lightweight EQ mount that can securely hold their imaging equipment while tracking desired celestial objects with high accuracy.
The HEM27 EC version comes with Real-time periodic error correction (RPEC). This means that the HEM27 EC mount head comes with a high precision RA axis encoder that delivers incredible tracking accuracy. With this feature, many users will choose to image the night sky without guiding.
iOptron rates this mount as having a payload capacity without counterweight of 29.74 lbs, and an OTA size of ~220 mm. Video is for demonstration purposes only.
The body of the HEM27 EC Hybrid EQ mount head is made from black anodized, CNC machined metal for a rugged platform in an appealing aesthetic able to accompany you on many observations and imaging sessions to come! The body comes complete with a dual saddle (Vixen and Losmandy D-style) and an internal cable management system so you will have no hanging exterior cables or moving parts. A unique feature of the HEM27EC mount head is the electronic friction brake and power-down location memory that allows the mount to safely stop and resume GoTo slewing or tracking, even if there is an abrupt power loss. This means you will not need to re-align or start from the beginning and can make the most of your night!
All the Necessary Accessories
The iOptron HEM27EC hybrid strain wave mount comes with all the essentials needed: the HEM27 mount with RA encoder, an 8409 Go2Nova hand controller with Wi-Fi capability, an iPolar electronic polar scope, a dual Vixen-/Losmandy-D-style saddle, and a soft carrying case.
Hybrid Strain Wave Drive with Right Ascension Encoder
The strain wave mount system from iOptron provides high payload capacities in small and lightweight form factors. This HEM27 mount with right ascension encoder weighs in at just over 8 pounds and can carry up to 29.74 pounds! Talk about weight-to-payload efficiency! And all of this is achieved without the need for a counterweight and shaft! Tracking accuracy is additionally improved with the inclusion of the RA axis encoder.
Go2Nova 8409 Hand Controller
This hand controller with built-in WiFi makes controlling the GoTo HEM27EC mount a breeze! With a large database of objects–from galaxies and nebulae to the planets and other objects in our solar system–you have endless options for exploring the night sky! The controller itself features a 4-line, 21-character backlit LCD screen and backlit buttons to see the controls in dark, observation settings. The Go2Nova 8409 also allows slewing at nine different speeds in order to keep the object under observation within view of the camera or eyepiece. This hand controller utilizes a USB port for connection to a computer and for firmware updates. It also has a Wi-Fi adapter for control with a computer or tablet.
iPolar Electronic Polarscope
With iPolar, accurate polar alignment is simple! All you have to do is place the plus symbol over the graphical representation of the celestial pole’s location. When these two symbols are aligned, they represent a precise polar alignment, allowing you to get the best performance possible from your HEM27 EC hybrid strain wave equatorial mount. The iOptron iPolar utilizes an electronic camera that is aligned with both the axes of your mount. The downloadable Windows software processes the camera’s images to calculate the true location of the celestial pole (north or south) and then guides you through any adjustments needed to align your mount precisely to the pole. Gone are the days of crouching behind a “through the mount” polar scope! Instead, the iPolar facilitates making altitude and azimuth adjustments by just glancing at your PC’s monitor. This system needs as few as four stars to locate the pole and can do so even when the pole location itself is blocked by clouds, tree branches or other obstructions. Please note this mount comes with iPolar built-in, not the standalone unit pictured.
Soft Carrying Case
Included with the HEM27EC mount head is a convenient carry case. This case will protect your mount during times of storage and transportation. You can rest assured that your equipment will be safe whether you are moving it to your favorite backyard viewing spot or taking it to a star party.
Perfect For Traveling or At-Home Observing
Looking for a high performance travel mount or powerful backyard mount? This iOptron HEM27EC is the perfect solution! Thanks to the strainwave technology, there is no need to lug around a counterweight during travel, and the mount head itself only weighs 8lbs. This HEM27EC effortlessly carries small portable refractors and is fitted with built-in WiFi within the hand controller, making it perfect for on-the-go imaging. For backyard observing, the almost 30 lb payload capacity allows support of larger, more robust telescopes, and gives you the option to mount a plethora of accessories as well. Also, Enjoy accurate tracking with integrated RPEC and precision encoders, and rest assured knowing your equipment is safe with the electronic friction brake during sudden power loss. With features like these, the iOptron HEM27EC Hybrid Equatorial Mount earns our High Point Scientific Mount Classification Badge of New Wave Harmonic!























Keith H. Verified Buyer –
I started out this hobby with an Atlas EQ mount but quickly found myself wanting to skip club events to avoid having to drag that big chunk of cast iron out to the field and back at 2am. Even setting up in my own backyard required using a dolly to tow out 80 pounds of equipment.
Not anymore . . . The biggest feature of this mount is weigh
t… or lack thereof. My entire setup now weighs 21 pounds. 8 lbs. for the HEM27EC, 5 lbs. for the carbon fiber tripod, and 8 lbs. for the RedCat51/ASI2600/ASIAIR. Since the mount and tripod are so light, I don’t separate them. My entire setup takes less than 10 minutes to be ready for polar alignment after I park my car at the remote dark sky site. Did I also mention I’m now completely out of the counter-weight business? Yeah, those doorstops are leaving with the Atlas. Buh, Bye . . .
There is certainly a reduction in wires using this mount. First, you have one power wire from your battery up to the base of the mount. Then your power travels internally to the DEC plate DC plug to power your camera, computer, ect. The DC connector center pin on the base of the mount is 2.5mm, where the other plugs are 2.1mm center pins. The max amperage for the DC distribution is 4 amps, which I’m close to when turning the dew heaters up over 70%. This would be my one criticism; I’d like to see a more skookum DC amperage rating and more robust power connectors such as Anderson Power Poles. You can never go wrong with having excess amperage handling capability.
The handset has a Wi-Fi access point built into it so you can control the mount using station mode. I found this to work surprisingly well and eliminates another wire. I also found controlling the mount using my iPad and iPhone with Sky Safari to be very easy. All of the mount’s “brains” are in the handset which is a good thing since replacing the handset is easier than an internal circuit board. The USB and other data sockets on the base of the mount are just “pass-throughs” up to the DEC plate. If you’re using USB control from your computer to the mount, it needs to be connected to the base of the handset, not the mount even though there is a USB-A socket on both. There is no holder for the handset, but there is a nice flat spot on the top of the mount to stick a 4″ square of Velcro for the handset where it will be clear of the DEC plate.
At first I wasn’t sure about having the worm drive on the DEC axis since the competing mount has 2 harmonic drives. But now that I’ve gotten a few hours experience with this mount I believe that the HEM is the superior solution. The DEC plate rotates extremely smooth with the clutch released, making it very easy to perfectly balance your rig on the DEC axis. Since the worm drive doesn’t have to fight any imbalance, it can go about its business while saving several pounds compared to having a second harmonic drive. I am not certain if there are encoders on the DEC axis, or if they’re even necessary.
The harmonic drive (search on YouTube, they’re pretty cool) with encoders on the RA axis is what this mount is all about. With a 480:1 reduction ratio, there is no need for counterweights. Hallelujah!! Even with that gear reduction ratio, the mount still moves at a very rapid speed when slewing at max rate. It is also extremely quiet in both axes. I bought the HEM27A (non-EC) for my wife’s C-8 and it slings that scope around with authority and tracks extremely well visually. Tracking for AP has been excellent with the HEM27EC. Using my RedCat51 and ZWO 120mm guide scope, I consistently get guiding numbers between .25″ and .75″ on both axes – usually closer to .25″. As for the encoder, I get round stars shooting unguided with a 300 second exposure. I could easily turn off the guide scope when shooting shorter exposures.
After 3 months using this mount, I cannot think of one thing I miss about the Atlas – except having to get a gym membership. Being able to set up and break down in less than 10 minutes changes your whole perspective on going to club events or remote sites. So far, I consider this mount one of my best purchases for the AP hobby and worth every penny.