iOptron 5.5 lb Counterweight for CEM70, GEM45, CEM40, iEQ45 and More
Part Number: 8027-05
Precision Balance for Larger Payloads
When your telescope setup starts to grow—adding a guide scope, camera, filter wheel, or heavier optics—maintaining perfect balance becomes more than a luxury; it’s essential. The iOptron 5.5 lb (2.5 kg) counterweight is designed to help you fine-tune your balance on medium-to-heavy-duty iOptron equatorial mounts, ensuring accurate tracking and reducing strain on the drive motors.
Whether you're refining an astrophotography rig or rebalancing after adding a new dovetail plate, the #8027-05 counterweight gives you more flexibility in load management than the standard 11 lb weights alone.
Designed for 28mm Counterweight Shafts
This counterweight is machined to fit 28mm (1.1") diameter counterweight shafts, which are standard on many of iOptron’s most capable mounts. The compression ring clamp system secures the weight without marring your shaft’s finish, using a brass-tipped hand knob to evenly distribute clamping pressure.
The compact body of the counterweight—measuring 5.05" in diameter and 2.07" in height—makes it easier to stack multiple weights if needed, or position it precisely for balance without overextending the shaft.
Compatible Mounts
The iOptron 5.5 lb counterweight is compatible with the following mounts that use 28mm counterweight shafts:
⚠️ Compatibility Note for CEM40 Users: Early production CEM40/CEM40EC mounts were shipped with 20mm counterweight shafts. Later models were upgraded to 28mm. Please verify your shaft diameter before ordering.
Balance Up to 45 Pounds with Optional Accessories
Most of these mounts ship with two 11 lb counterweights, which together can balance a payload of roughly 25 pounds. But if you're pushing toward the upper end of your mount’s rated capacity (such as a fully loaded imaging train), you may need one or more 5.5 lb counterweights to dial in your system.
Pairing this weight with the iOptron #8026 counterweight shaft extension gives you the added shaft length and mass capacity needed to balance setups up to 45 lbs on mounts like the CEM70 and GEM45.
Technical Specifications
| Feature |
Specification |
| Weight |
5.5 lbs (2.5 kg) |
| Fits Shaft Diameter |
28mm (1.1") |
| Material |
Cast metal with protective finish |
| Clamp Mechanism |
Brass-tipped screw with hand knob |
| Attachment Style |
Compression ring (no shaft damage) |
| Diameter |
5.05" (128mm) |
| Height |
2.07" (52.5mm) |
| Finish |
Matte black |
| Compatibility |
CEM70, GEM45, CEM60, CEM40*, iEQ45/Pro |
Observing Tip
Even with a perfectly balanced OTA, small accessories can subtly tip the system out of alignment. Use this 5.5 lb counterweight to fine-tune balance when changing cameras, adding off-axis guiders, or using extended dew shields. Proper balance isn’t just about weight—it’s about torque—and this compact weight gives you the flexibility to adjust the moment arm without loading on a full 11 lbs.
Final Thoughts
The iOptron 5.5 lb Counterweight (#8027-05) is a must-have accessory for serious astrophotographers and advanced visual observers using mid-capacity equatorial mounts. Designed for durability, smooth operation, and safe mounting, it lets you extend your system’s payload capabilities with confidence.
Whether you're upgrading your gear or refining your balance for better guiding, this counterweight adds the precision your mount needs to perform its best.
