iOptron HEM44 Mount

Hybrid StrainWave Drive: A 44 lbs Payload on a 13.65 lbs Mount

The core of every HEM44 is its hybrid drive. The RA axis uses a StrainWave gear with a 640:1 reduction ratio and a 270-second period, delivering the zero-backlash response and high torque that precise long-exposure tracking demands. The DEC axis uses a backlash-free worm/belt system for smooth slewing and guiding corrections without the cost and weight of a second harmonic drive. For payloads up to 44 lbs, you can run the HEM44 completely counterweight-free, dramatically reducing what you carry into the field. For larger setups, the optional counterweight shaft and 10 lbs counterweight raise the capacity to 55 lbs (25 kg).

EC Versions: High-Precision RA Encoder and Realtime PEC

The HEM44EC adds a high-precision encoder on the RA axis that constantly monitors the mount's position. This feedback loop enables Realtime PEC (Periodic Error Correction), which actively corrects the drive's minute mechanical variations as they happen, before they become visible in an image.

• Rounder stars: Smoother, more accurate raw tracking than the standard HEM44, crucial for high-resolution imaging.
• Less guiding effort: Reduced reliance on aggressive autoguiding corrections.
• Unguided potential: High-quality unguided exposures become practical with a well-aligned mount and a short-to-medium focal length telescope.

Choose Your HEM44 Version

All HEM44 versions share the same hybrid StrainWave drive, 44 lbs counterweight-free payload, 13.65 lbs head, Go2Nova® 8409 controller and built-in Wi-Fi. They differ in two ways: whether the RA axis has a high-precision encoder, and whether the internal iPolar electronic polar scope is included.

• HEM44 Mount: The core hybrid mount. An excellent choice for visual observers and imagers who autoguide, or who already have an electronic polar alignment solution.
• HEM44 Mount w/ iPolar: Adds iOptron's internal iPolar electronic polar scope for fast, screen-based polar alignment with ~30 arcsec precision from a Windows PC.
• HEM44EC Mount: Adds the high-precision RA encoder for Realtime PEC, for imagers who want the highest tracking accuracy and already have their own polar alignment method.
• HEM44EC Mount w/ iPolar: The complete package: RA encoder with Realtime PEC plus the internal iPolar, for dedicated astrophotographers chasing unguided or high-resolution imaging.

Go2Nova Control and Field-Ready Design: 212,000 Objects, Wi-Fi and 2 x 12V Power

The proven Go2Nova® 8409 hand controller features a database of ~212,000 objects and a maximum slew speed of 4.5º/sec. Built-in Wi-Fi connects the HEM44 to planetarium and session management software on your PC, tablet or smartphone, while a USB port and an ST-4 compatible autoguide port handle wired control, firmware updates and guide cameras.

• Electronic Friction Brake: Locks the axes when power is cut, so your telescope cannot swing unexpectedly during setup or a power loss.
• Power-Down Memory: The mount remembers its position and alignment after a power loss, so you can resume without starting over.
• Integrated Cable Management: Two 12V DC outputs (3A max) and one USB 2.0 port near the saddle reduce cable snags as the mount tracks.
• Dual Saddle: The Vixen and Losmandy-style dovetail saddle accepts nearly any telescope optical tube.

HEM44 vs. Traditional GEMs: The StrainWave Advantage

StrainWave technology represents a significant shift from traditional German equatorial mount (GEM) designs. While a conventional worm-gear GEM offers a familiar platform for experienced imagers, the HEM44 offers a compelling alternative focused on portability.

• Traditional GEM Advantage: Many imagers are accustomed to the behavior of worm-gear systems, whose periodic error is well understood and easily managed with autoguiding.
• HEM44 Advantage: The exceptional payload-to-weight ratio. A conventional GEM carrying 44 lbs needs a heavier head and heavy counterweights, while the HEM44's 13.65 lbs head runs counterweight-free for most setups, making it vastly easier to transport to remote dark-sky sites. The EC versions add Realtime PEC for tracking accuracy on top.