Explore Scientific 3-inch Self-Centering Focuser - ES-FOC3

Designed for astrophotographers who demand uncompromising performance, the Explore Scientific 3-inch Self-Centering Focuser delivers smooth, precise control and exceptional load-bearing capacity to support even the most complex imaging trains. With its zero-flex compression system and high-end rack-and-pinion mechanism, this focuser ensures perfect alignment, minimal backlash, and stable operation during long exposures.

The 84.5mm draw tube travel eliminates the need for extension tubes, while 14 internal baffles enhance contrast by suppressing internal reflections. The self-centering compression ring locks your imaging gear in place with uniform pressure to eliminate tilt and sag—even under heavy load. Engineered for durability and versatility, it’s compatible with 2” and 3” accessories, electric focusers, and threaded adapters via its M82 x 1.25 pitch threading.

A no-tool back cell adapter allows fast installation and 360° rotation using hand-tightened knobs. Whether you're doing planetary imaging or deep-sky astrophotography, this focuser provides the precision and strength needed for professional results.

⚠️ Compatibility Notes:

• White-tube Explore Scientific refractors with threaded back cells must be shipped to Explore Scientific for adapter installation.
• The FPL53-165CF requires a separately purchased back cell adapter.
• The TED15208CF does not require an adapter — this focuser fits directly.
  

CA Residents: Prop 65 WARNING(S)

⭐ Features & Benefits

• Self-Centering Compression System – Applies uniform pressure for tilt-free, flex-free stability
• 17 lb Load Capacity – Supports complex astrophotography setups without image shift
• Helical Rack-and-Pinion Focus Mechanism – Marine-grade PTFE silicone lubrication ensures smooth, backlash-free movement
• 84.5mm Draw Tube Travel – Eliminates need for extra extension tubes
• 14 Internal Baffles – Suppress reflections and enhance contrast
• 9:1 Dual-Speed Microfocuser – Stainless steel ball bearings provide precise fine-focus control
• Twist-Lock Compression Ring – Securely holds both 2” and 3” accessories
• M82 x 1.25 Threading – Accepts threaded adapters for custom imaging setups
• Teflon Rotation Ring – Enables smooth 360° rotation without disturbing alignment
• Tool-Free Installation – Includes hand-knob adjustable back cell adapter (120mm–140mm refractors)
• Electric Focuser Compatible – Upgrade-ready for motorized focusing systems
• Black Anodized Aluminum Construction – Rugged, professional-grade build

🌟 Who It’s For

• Astrophotographers using heavy imaging setups needing rock-solid focus
• Refractor telescope users seeking zero-flex, high-precision focusing
• Observers wanting smooth manual and motorized focusing in one unit
• DIY telescope builders or upgraders needing compatibility and versatility
• Explore Scientific telescope owners looking to maximize performance

🎯 What You’ll Be Able to Do

• Achieve perfect focus with zero shift—even with 17 lbs of gear attached
• Rotate your imaging train smoothly without tools or loss of alignment
• Improve image contrast with baffled light suppression
• Customize your setup with threaded accessories and electric focusers
• Use the same focuser across multiple scopes with the right adapters

🎒 What’s Included

• 3” Self-Centering Focuser Assembly
• No-tool back cell adapter for Explore Scientific 120mm–140mm refractors
• Twist-lock compression ring system (fits 2” and 3” accessories)
• M82 x 1.25 threaded draw tube
• 3” to 2” adapter
• Instruction manual
• 2-Year Limited Warranty

Specs

Warranty Information:

This product is covered by a Limited One-Year USA Warranty, valid when registered within 60 days of purchase. To activate your warranty, please visit the Explore Scientific website and complete the registration form at:

www.explorescientific.com/pages/product-registration