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Explore Scientific

Explore Scientific 3″ Self-Centering Focuser for 152/165 mm Refractors (ES-FOC3)

Explore Scientific 3″ Self-Centering Focuser for 152/165 mm Refractors (ES-FOC3)

$949.99
$949.99
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Shipping calculated at checkout.

The Explore Scientific 3″ Self-Centering Focuser (ES-FOC3) is a premium, heavy-duty focuser built for large refractor telescopes, specifically 152 mm and 165 mm models. Designed for both visual astronomers and astrophotographers, it offers a self-centering compression system that keeps accessories perfectly aligned with zero tilt. The smooth rack-and-pinion mechanism, generous 84.5 mm of travel, and stability under heavy imaging loads make it an ideal upgrade for those seeking precision, durability, and performance.

Features

  • Self-centering compression system ensures even pressure on the drawtube for maximum stability.

  • Large 3″ drawtube accommodates wide-field and heavy imaging accessories.

  • 84.5 mm of drawtube travel provides excellent focus range and back-focus flexibility.

  • 9:1 fine-focus helical rack-and-pinion system offers smooth, backlash-free adjustments.

  • Supports up to 17 lb (7.7 kg), ideal for cameras, filter wheels, and large eyepieces.

  • Includes adapters for both 2″ and 3″ accessories, expanding compatibility.

  • Precision-machined aluminum construction with a durable anodized finish.

Specifications

Specification Detail
Model Number ES-FOC3
Drawtube Diameter 3″ (76.2 mm)
Drawtube Travel 84.5 mm (approx. 3.32″)
Focus Mechanism Rack and pinion with 9:1 fine adjustment
Load Capacity 17 lb (7.7 kg)
Drawtube Thread M82 × 1.25
Telescope Compatibility Explore Scientific 152 mm & 165 mm refractors (also adaptable to other refractors with correct adapter)
Weight Approx. 2.6 kg (5.7 lb)
Accessory Compatibility 2″ and 3″ eyepieces or imaging accessories

What’s Included

  • Explore Scientific 3″ Self-Centering Focuser

  • 2″ and 3″ twist-lock/compression adapters

  • M82 × 1.25 threaded drawtube

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Frequently Asked Questions

With a beginner telescope you can see a surprising amount — the craters and mountains on the Moon, the rings of Saturn, the moons of Jupiter, and star clusters like the Pleiades. As you get more comfortable, you can also spot nebulae and distant galaxies. Not sure which beginner telescope is right for you? Check out our Telescope Buying Guide.
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