Explore Scientific 102mm f/7 Carbon Fiber FCD100 ED Triplet Refractor

Explore Scientific 102mm FCD100 Carbon Fiber ED Triplet Apochromatic Refractor (ES102CF-FCD100)

A 4" apochromatic refractor has long been the benchmark for serious observers looking to balance optical performance with portability. The Explore Scientific 102mm FCD100 Carbon Fiber Triplet is a premium example of that tradition—built around high-end glass, a durable carbon fiber tube, and a precision dual-speed focuser that makes it equally capable for visual astronomy and astrophotography.

With excellent color correction, pinpoint star images, and a rock-solid construction that resists flexure and thermal shift, this telescope delivers serious performance for stargazers who want sharp views and dependable imaging capability in the field or in the backyard. Whether you’re hunting lunar detail at high power, chasing down faint planetary nebulae, or capturing wide-field astroimages with a cooled camera, the ES102 performs like a telescope twice its price.

Precision Glass for Color-True Views

At the heart of this refractor is a 102mm f/7 triplet objective that uses Hoya FCD100 extra-low dispersion (ED) glass as its center element. FCD100 is the performance equivalent of Ohara’s FPL-53—known throughout the industry as one of the finest ED glass types available.

By minimizing chromatic aberration, this triplet design delivers color-true, high-contrast images of the Moon, planets, and stars. The false color halos seen in doublets or achromats are virtually eliminated, even at high magnifications, and your targets appear clean, crisp, and naturally colored. For astrophotographers, that translates to tighter stars and fewer post-processing headaches.

The optics are finished with Explore Scientific’s proprietary EMD™ enhanced multilayer coatings for maximum light transmission and contrast. You’ll see more faint detail, deeper into nebulae, and more contrast across planetary surfaces thanks to minimal scatter and internal reflection.

Carbon Fiber Strength and Thermal Stability

The OTA and dew shield are constructed from epoxy-encapsulated carbon fiber, which is incredibly strong, light, and dimensionally stable. This makes the ES102 significantly lighter than comparable aluminum-tube scopes—an asset for observers who are traveling, working from smaller mounts, or trying to balance a heavy imaging train.

Just as importantly, carbon fiber resists thermal expansion. Unlike metal tubes, which contract and expand noticeably with temperature changes, the carbon fiber body of the ES102 helps maintain precise focus throughout your session. That stability is especially useful for long-exposure imaging or visual observing in rapidly cooling evening temperatures.

Fine Focus Control with a Hexagonal Backbone

The included 2.5" hexagonal focuser is built to deliver both mechanical rigidity and ultra-fine focusing precision. The focuser features dual-speed control with a 10:1 microfine knob, letting you make the small focus adjustments critical for high-resolution observing and pinpoint astrophotography.

The drawtube features graduated markings in millimeters and centimeters for easy return to focus positions, while the integrated tension adjustment and locking system holds heavy eyepieces, diagonals, or cameras securely in place without image shift.

The focuser’s rotating design makes it easier to frame targets or orient a camera sensor without disturbing the optical train. A non-marring 2" compression ring holder ensures secure, damage-free attachment of accessories.

Also included are two 2" extension tubes, allowing you to easily reach focus whether you’re using a diagonal and eyepiece or running a camera and flattener directly in the optical path.

Built for Real Observing Conditions

Like all Explore Scientific air-spaced triplets, the ES102 includes a host of thoughtful features that make it easier to use in the field and more rewarding at the eyepiece.

• The dew shield slows dew formation, increases contrast, and reduces stray light—especially helpful near neighborhood lights or on dewy summer nights.

• The interior of the tube is baffled and blackened to enhance contrast and eliminate reflections.

• The collimatable lens cell is factory-aligned and rarely needs adjustment—but if it does, it’s accessible and user-serviceable with included instructions.

• A metal slip-on dust cap protects the optics during storage or transport.

Mounting and Transport Made Easy

The scope comes with dual split mounting rings and a Vixen-style dovetail rail, compatible with most medium-capacity mounts including popular models from Celestron, iOptron, and Sky-Watcher. A top-mounted stabilizer bar doubles as a carry handle, making it easier to transport the scope and install it on your mount—even in the dark.

A finderscope base is pre-installed on the OTA, ready to accept a straight-through or right-angle finder, red dot, or reflex sight of your choice.

With a 714mm focal length, the ES102 strikes a perfect balance: long enough for detailed planetary views, but short enough to deliver wide fields and excellent framing for large deep-sky targets. Add a field flattener or reducer, and the ES102 becomes a capable imaging platform for full-frame or APS-C sensor astrophotography.

Lifetime Warranty, Lifetime Value

Every Explore Scientific ES102 FCD100 Carbon Fiber triplet is individually serial numbered and backed by a one-year limited warranty, which extends to a Lifetime Transferable Product Warranty when registered within 60 days of purchase. This warranty is valid for the life of the scope—even if it changes hands—making it an investment that holds its value over time.

Specifications

• Optical design: Air-spaced apochromatic triplet refractor

• Aperture: 102mm (4")

• Focal length: 714mm

• Focal ratio: f/7

• Glass type: Hoya FCD100 ED glass (FPL-53 equivalent)

• Tube construction: Carbon fiber with retractable dew shield

• Focuser: 2.5" dual-speed rotating hexagonal focuser

• Drawtube scale: Graduated in mm and cm

• Back focus accessories: Includes two 2" extension tubes

• Mounting rings: Dual split rings with Vixen-style dovetail

• Top handle: Integrated carry handle/stabilizer bar

• Finderscope base: Installed

• Dust cap: Slip-on metal

• Weight (OTA only): ~11 lbs