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Explore Scientific FCD100 Series 127mm f/7.5 Triplet APO Refractor - Carbon Fiber with 2.5" HEX Focuser

SKU ES-FCD100-127075-CF-01
Original price $2,799.99 USD - Original price $2,799.99 USD
Original price
$2,799.99 USD
$2,799.99 USD - $2,799.99 USD
Current price $2,799.99 USD
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  • 127mm (5") Aperture
  • f/7.5 Focal Ratio & 952mm Focal Length
  • Air-Spaced Triplet Apochromat with HOYA FCD100 ED Glass
  • Carbon Fiber Optical Tube Weighs 14 lbs (6.35 kg)
  • 2.5" Dual-Speed HEX Focuser with 10 lbs (4.5 kg) Load Capacity
  • EMD (Enhanced Multilayer Deposition) Coatings
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See exactly how your targets fit with the Explore Scientific FCD100 Series 127mm f/7.5 Triplet APO Refractor - Carbon Fiber with 2.5" HEX Focuser, on real sky survey data.

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See exactly what the Explore Scientific FCD100 Series 127mm f/7.5 Triplet APO Refractor - Carbon Fiber with 2.5" HEX Focuser shows you, on real sky survey data.

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  • Explore Scientific FCD100 Series 127mm f/7.5 Triplet APO Refractor - Carbon Fiber with 2.5" HEX Focuser

    The Explore Scientific FCD100 Series 127mm f/7.5 Triplet APO Refractor combines a 952mm focal length with a true air-spaced triplet optical system for imaging and visual observation. Its premium HOYA FCD100 ED glass element delivers true apochromatic color correction, housed in a carbon fiber tube that keeps the total OTA weight to just 14 lbs (6.35 kg). The 2.5" HEX focuser supports heavy imaging gear up to 10 lbs (4.5 kg).

    The 127mm f/7.5 Triplet: Apochromatic Correction with HOYA FCD100

    At the heart of this refractor is its 127mm air-spaced triplet objective, which uses a genuine HOYA FCD100 ED glass element to achieve true apochromatic performance. This design virtually eliminates chromatic aberration, the false color or purple fringing seen in less-corrected instruments.

    The result is pinpoint stars against a black background and high-contrast detail on planetary targets. The f/7.5 focal ratio provides a balance between image scale for smaller objects and a field of view wide enough for many larger nebulae, making it a highly capable instrument for both visual and photographic pursuits.

    Carbon Fiber Construction: 14 lbs and Thermal Stability

    The optical tube is constructed from carbon fiber, and the construction ensures portability without compromising rigidity or thermal stability. This keeps the total OTA weight at just 14 lbs (6.35 kg), making the 127mm aperture manageable on a wide range of medium-duty equatorial mounts.

    For astrophotography, a light tube also means less weight on the mount alongside the camera and accessories. Explore Scientific presents the carbon fiber 127 as a ready-to-go option for grab-and-go observing or serious imaging setups.

    The 2.5" HEX Focuser: A 10 lb Payload Capacity for Imaging

    Astrophotography puts the weight of the camera and its accessories on the focuser. The 2.5" HEX focuser supports heavy imaging gear up to 10 lbs (4.5 kg), with smooth and precise focusing.

    A dual-speed mechanism allows for coarse adjustments to find focus quickly and fine adjustments to achieve critical sharpness for high-resolution imaging.

    EMD Coatings

    EMD-enhanced coatings are among this telescope's features, and it delivers brilliant contrast and pinpoint detail. Multi-layer coatings reduce reflections that can cause ghosting and lower contrast.

    The Included 2-inch 99% Reflective Diagonal

    For visual observers, this telescope includes a high-quality 2-inch diagonal with 99% reflective coatings. This accessory is critical for comfortable viewing at high angles and ensures that the light gathered by the objective lens is not diminished before it reaches the eyepiece.

    The 2-inch barrel accommodates wide-field, low-power eyepieces for sweeping views of star fields and large nebulae like the North America Nebula (NGC 7000). The 2026 catalog lists the FCD100 Series diagonal with a 1.25-inch adapter (in the aluminum models' columns); 1.25-inch eyepieces are the usual choice for higher magnification on the Moon, planets and double stars.

    Building an Imaging Train with the 127mm FCD100

    With its 952mm focal length and apochromatic optics, the 127mm FCD100 is a formidable imaging platform. The 2.5" HEX focuser carries the camera and accessories, up to 10 lbs (4.5 kg).

    For round stars toward the corners of larger sensors, a field flattener or focal reducer/flattener is recommended, as with other refractors. The included Hybrid Finder Scope Base accepts legacy Explore Scientific finder brackets and mini dovetail-type finder brackets.

    FCD100 127mm Carbon Fiber vs. Aluminum

    Explore Scientific offers the 127mm FCD100 in both carbon fiber and aluminum tube versions; the 2026 catalog notes the FCD100 Series is also available in lightweight carbon fiber. This carbon fiber model weighs 14 lbs (6.35 kg).

    Explore Scientific's published weight for the aluminum version is inconsistent (18 lbs and 10 kg in the same catalog row), so we do not quote a weight difference. Choose the carbon fiber version if a lighter tube matters most for your mount and travel.

  • What kind of mount is required for the Explore Scientific 127mm FCD100 refractor?

    The Explore Scientific 127mm FCD100 weighs 14 lbs (6.35 kg) and requires a robust equatorial mount for stable imaging. Choose a mount whose imaging capacity comfortably exceeds the telescope plus your camera and accessories. The FCD100 series uses a "Universal Vixen Style" mounting plate, so ensure your mount's saddle accepts a Vixen-style dovetail.

    How does the HOYA FCD100 glass in this 127mm refractor compare to other ED glasses?

    HOYA FCD100 is a premium extra-low dispersion (ED) glass with optical characteristics often compared to fluorite. It allows designers to create triplet objectives that achieve a very high level of color correction, virtually eliminating chromatic aberration. The result is brilliant contrast and pinpoint detail.

    What can I expect to see of the Orion Nebula (M42) with the Explore Scientific 127mm FCD100?

    With its 127mm aperture and apochromatic optics, you will resolve fine detail within the Orion Nebula (M42). The Trapezium cluster at its heart will be cleanly split into its four primary stars (and with good seeing, the E and F stars may be visible). The faint, nebulous "wings" of the nebula will show intricate structure and excellent contrast against a dark sky background, especially with a low-power, wide-field 2-inch eyepiece.

    Is the 952mm focal length of the ES 127mm FCD100 a good match for imaging the Andromeda Galaxy (M31)?

    The 952mm focal length provides an excellent image scale for many deep-sky objects. While the Andromeda Galaxy (M31) is exceptionally large, this focal length will perfectly frame its bright core and extensive dust lanes on a typical APS-C sensor. To capture the full 3-degree apparent width of M31 in a single frame, a focal reducer would be required to shorten the focal length and widen the field of view.

    Why is the carbon fiber tube on the Explore Scientific 127mm FCD100 important for astrophotography?

    The carbon fiber construction keeps the weight to 14 lbs (6.35 kg) without compromising rigidity or thermal stability. A lighter tube leaves more of the mount's capacity for the camera and accessories.

    What accessories do I need to start using the Explore Scientific 127mm FCD100 refractor?

    This is an optical tube assembly (OTA) supplied with a 99% reflective 2-inch diagonal and a Hybrid Finder Scope Base. To begin observing, you will need at a minimum:

    • A sturdy equatorial mount
    • Eyepieces (both 2-inch and 1.25-inch formats)
    • A finder scope or red-dot finder that fits the included base

    What is the benefit of the 2.5" HEX focuser on the ES 127mm FCD100?

    The 2.5" HEX focuser supports heavy imaging gear up to 10 lbs (4.5 kg) and offers smooth and precise focusing for high-magnification observing or astrophotography.

    Is the Explore Scientific 127mm FCD100 a good telescope for viewing Jupiter?

    Absolutely. The apochromatic triplet optics provide high-contrast views with virtually no false color. With the 127mm aperture and 952mm focal length, you can easily use high-power eyepieces to resolve details like Jupiter's main cloud bands, the Great Red Spot, and the shadows of its moons transiting the planet's disk. The views will be sharp, detailed, and color-pure.

    What finder scope can I use with the included Hybrid Finder Scope Base?

    The included Explore Scientific Hybrid Finder Scope Base (ES-FB2N1-00) is designed to be versatile. It accepts legacy Explore Scientific finder scope brackets as well as finder scopes that use a mini dovetail-type bracket, such as those from Vixen, Synta, and Celestron. This gives you a wide range of options for attaching a finder scope.

    Can I use 1.25" eyepieces with the included 2-inch diagonal on the 127mm FCD100?

    Explore Scientific's 2026 catalog lists the FCD100 Series 99% reflective 2-inch diagonal with a 1.25-inch adapter (in the aluminum models' columns). With a 1.25-inch adapter, the diagonal allows you to use both 2-inch eyepieces for wide-field, low-power views and standard 1.25-inch eyepieces, which are typically used for achieving higher magnifications for planetary and double star observing.

  • Aperture 127mm (5")
    Focal Ratio f/7.5
    Focal Length 952mm
    Optical Design Air-Spaced Triplet Apochromat
    Glass Type HOYA FCD100 ED
    Focuser 2.5" Dual-Speed HEX Focuser
    Tube Material Carbon Fiber
    Coatings EMD (Enhanced Multilayer Deposition)
    GTIN 812257017812
    Focuser load capacity 10 lbs (4.5 kg)
    OTA weight 14 lbs (6.35 kg)
    Mount included No (optical tube only)
    • Explore Scientific 127mm FCD100 Carbon Fiber OTA

      × 1

    • 99% Reflective 2-inch Diagonal

      × 1

    • Hybrid Finder Scope Base (ES-FB2N1-00)

      × 1

  • Explore Scientific Warranty