iOptron HAE43EC Harmonic Mount Review

HAE43EC (enhanced encoders)


Product: iOptron HAE43 Strain Wave AZ/EQ Mount with High Precision Encoders

Manufacturer: iOptron

Current Price: $4248

What are Strain Wave Mounts?

Strain wave telescope mounts, also known as harmonic drive telescope mounts, are a type of motorized mount used to control the movement of telescopes. This type of mount is rapidly being adopted by manufacturers because of the advantages.

The mount consists of three main components: a central gear, an input shaft, and a flexible outer ring. The input shaft rotates the central gear, which then rotates the outer ring. As the outer ring rotates, it causes the telescope to move in the desired direction.

Strain Wave gear diagram

Are they better than more traditional mounts?

One of the key advantages of strain wave telescope mounts is their high precision and accuracy. They are designed to have very low backlash, which is the amount of play or movement that can occur between the gears, which can be particularly troublesome in the declination axis for many “traditional gear” telescope mounts. This makes harmonic drive mounts particularly useful for astrophotography and other applications where precise positioning is critical. Some users have reported larger periodic errors with this type of mount. Periodic error is the cyclical variation of position caused by minor irregularities of the gears. If true, shorter focal length telescopes would be less effected. Many modern mounts do include periodic error correction built-in, which would minimize this effect. For photogrophy, guiding corrections might need to be made with shorter intervals.

Another advantage of strain wave mounts is their compact size and low weight. They are often used in portable telescope setups, as they can be easily transported and set up in the field. Surprisingly, these low weight mounts can carry large payloads without the need for counterweights. For even heavier payloads, attachment of counterweights is possible.


Are there disadvantages?

One potential drawback of strain wave telescope mounts is their relatively high cost compared to other types of telescope mounts. However, their precision and accuracy make them a valuable investment for serious astronomers and astrophotographers who require precise control over their telescope movements.

What about the iOptron HAE43?

iOptron has a long history of making high-quality mid-priced astronomy gear. Along with some other manufacturers, the company has been an early adopter and innovator when it comes to this technology. The high-precision encoders add a new element to precise pointing and tracking!


  • Advanced strain wave gear system technology with high precision encoders
  • Payload capacity of 20 kg (44 lbs) with the mount weight of 5.5 kg (12 lbs, include dovetail saddle)
  • CNC machined
  • Unique friction brake to safely stop movement during a planned or unplanned power interruption
  • 270 second gear period
  • Go2Nova® hand controller with ~212,000 object database
  • Customer cable management system ready
  • Dual saddle (Vixen and Losmandy-D styles)
  • Built in zero position search and locator
  • Power down position and location memory
  • Integrated ST-4 autoguiding port
  • Built-in Wi-Fi (via hand controller)
  • USB port for firmware upgrade and computer control
  • Aluminum carrying case
  • Two year warranty


  • Computerized
  • Database: 212,000 objects
  • Drive type: Strain Wave
  • Encoders: no
  • Head design: equatorial or altazimuth
  • Capacity 44 lbs (20 kg)
  • Latitude range: 0 to 90 degrees
  • Mount head weight: 12 lbs (5.5 kg)
  • Periodic error correction: yes
  • Ports: DC 12v 5a, ST4 guiding port, USB
  • Telescope mounting rail: Dual Vixen and Losmandy
  • Warrantly: 2 years


iOptron produces excellent and reliable products. They are very high quality. And although they would not be considered low-price, the quality to price ratio is very high. In other words, you will get high quality at a reasonable price. If you don’t need as much payload capacity, and price is an issue, you can consider its smaller sibling: the iOptron HAE29 for $2098. If price is no object, and you need the highest precision, consider the iOptron HAE43EC for $4248. This model includes absolute encoders, which makes pointing highly accurate. You can’t go wrong with any of these models.


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