Explore Scientific 3X Focal Extender - 2"

Triple Your Eyepiece Collection with 3X Power

This 3X Focal Extender instantly expands the utility of your existing eyepieces. By placing it in your telescope's 2-inch focuser, you effectively give every eyepiece you own a second, higher-magnification version. An accessory case with three eyepieces now yields six distinct magnification choices, providing greater flexibility for targeting planets, double stars, and small deep-sky objects without needing to purchase a full new set of high-power eyepieces.

Telecentric Design: A True 3X Magnification Factor

Unlike a standard Barlow, the Explore Scientific Focal Extender uses a telecentric design. This multi-element system ensures light rays exit the extender parallel to the optical axis, which produces a fixed, true-to-spec magnification factor. Whether you're using it for visual work or attaching a camera, the 3X power remains consistent, eliminating the variability that can occur with Barlows when eyepiece or camera spacing is altered.

High-Contrast Views for 2" Eyepieces & Preserved Eye Relief

Optical quality is maintained through Enhanced Multilayer Deposition (EMD) coatings on all air-to-glass surfaces and edge-blackened lens elements. This combination maximizes light throughput while suppressing internal reflections, resulting in superior image contrast. A significant ergonomic advantage is that the extender preserves the native eye relief of the eyepiece in use, allowing you to enjoy the comfortable, long eye relief of a low-power eyepiece even at high magnifications—a crucial benefit for eyeglass wearers.

Focal Extender vs. Barlow: Why a 3X Telecentric Matters

While a traditional Barlow lens may be lighter or less expensive, its simple design introduces optical trade-offs. The telecentric focal extender is engineered for more demanding applications where optical consistency is paramount.

• Consistent Magnification: A Barlow's magnification changes with distance from the eyepiece. The 3X Focal Extender's telecentric design locks the magnification at 3X, which is critical for repeatable imaging setups.
• Maintained Image Quality: Telecentric extenders are better corrected for field curvature, keeping stars sharp across a wider field of view, especially in fast telescopes.
• Parallel Light Path: The parallel light rays exiting the extender are less demanding on complex eyepieces and are ideal for use with narrowband H-alpha filters, like those used for solar observing, which require a parallel beam of light for optimal function.