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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
Explore Scientific 3X Focal Extender - 1.25"

Explore Scientific 3X Focal Extender - 1.25"

by Explore Scientific
SKU ES-FE03-125
$139.99 - $139.99
$139.99
$139.99 - $139.99
$139.99
Price Match Policy!
  • Instantly triples the magnification of any 1.25" eyepiece
  • Telecentric optical design provides consistent magnification
  • Maintains the eye relief of the original eyepiece
  • Improves image quality compared to standard Barlow lenses
  • Ideal for high-power planetary viewing and imaging
1 in stock
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Explore Scientific 3X Focal Extender - 1.25"

    The Explore Scientific 3X Focal Extender instantly triples the power of any 1.25" eyepiece in your collection. This telecentric design turns three of your favorite low-power eyepieces into a versatile set offering six distinct magnifications, unlocking high-power views without sacrificing optical integrity or viewing comfort.

    Triple Your Magnification with a 1.25" Barrel

    This focal extender multiplies the utility of your existing eyepiece case. By inserting this 3X extender, you can achieve magnifications typically reserved for short focal length eyepieces, which often have tight, uncomfortable eye relief. It allows you to push the power on clear nights to resolve fine detail on Jupiter's cloud bands or split tight double stars, all while using your familiar, comfortable long-focal-length eyepieces.

    Telecentric Optics: A Stable 3X Magnification Factor

    Unlike a traditional Barlow lens, the Explore Scientific Focal Extender uses a multi-element telecentric design. This system ensures light rays exit parallel to the optical axis, delivering a true, fixed 3X magnification regardless of the distance between the extender and your eyepiece or camera sensor. This stability is critical for astrophotography, where precise focal length is required for accurate image scaling, and it eliminates the variable magnification that can occur with Barlows.

    • Consistent Magnification: The 3X power factor remains constant, providing predictable and repeatable results for both visual observation and imaging.
    • Maintained Eye Relief: You get to enjoy the generous eye relief of your lower-power eyepiece, a significant advantage for eyeglass wearers and for comfortable extended viewing sessions.
    • Improved Field Flatness: The telecentric design helps to reduce field curvature, resulting in sharper stars at the edge of the field compared to simpler amplifier lenses.

    Focal Extender vs. Barlow: Why the Telecentric Design Matters

    While both devices increase magnification, their optical approach is fundamentally different. A standard Barlow's magnification factor changes as you alter its spacing from the eyepiece, which can be unpredictable. The Explore Scientific Focal Extender's telecentric design offers superior optical correction and stability.

    This makes it the preferred choice for observers using premium, complex eyepieces or imagers who require a flat field and consistent focal length. The parallel light path is less demanding on eyepiece optics, preserving the original image quality without introducing additional aberrations.

  • What is the main difference between the Explore Scientific 3X Focal Extender and a standard 3X Barlow?

    The primary difference is the telecentric optical design of the Focal Extender. This provides a fixed, consistent 3X magnification regardless of spacing. A standard Barlow's magnification can vary depending on its distance from the eyepiece or camera sensor. The telecentric design also better preserves the eye relief of the eyepiece and provides superior optical correction across the field.

    How will the 3X Focal Extender affect my view of Saturn in an 8" f/10 SCT?

    In an 8" f/10 SCT (2032mm focal length), a 25mm eyepiece gives you 81x magnification. Adding the Explore Scientific 3X Focal Extender will increase that to 243x. This is an excellent magnification for resolving details like the Cassini Division in Saturn's rings and observing cloud bands on the planet itself, assuming steady atmospheric conditions.

    Does the Explore Scientific 3X Focal Extender change the eye relief of my eyepiece?

    A key benefit of the telecentric design is that it largely preserves the original eye relief of the eyepiece you use it with. This means you can achieve high power while still enjoying the comfortable, long eye relief of a lower-power eyepiece, which is especially beneficial for eyeglass wearers.

    Is the 3X Focal Extender a good choice for planetary imaging with a high-frame-rate camera?

    Yes, it is an excellent choice. The telecentric design provides a flat field and ensures the magnification is a consistent 3X, which is critical for planetary imaging. It effectively triples your telescope's focal length, increasing the image scale on your camera sensor to make planets like Jupiter, Saturn, and Mars appear larger and more detailed.

    Will this 1.25" focal extender work with my 2" eyepieces?

    No, this model is designed specifically for 1.25" eyepieces and accessories. It will not fit 2" eyepieces. You must use eyepieces with a 1.25" barrel.

    Is there a downside to using the Explore Scientific 3X Focal Extender?

    Like any device that triples magnification, the 3X Focal Extender will result in a dimmer image and make your telescope more sensitive to atmospheric instability (seeing). It requires good seeing conditions to deliver its best results. However, its superior optical design minimizes aberrations compared to simpler Barlow lenses.

  • Magnification 3X
    Barrel Size 1.25"
    Optical Design Telecentric
    GTIN 812257010394
  • Explore Scientific Warranty