The Explore Scientific FCD100 127mm APO pairs premium HOYA FCD100 extra-low dispersion glass with an air-spaced triplet design to deliver diffraction-limited views with virtually zero chromatic aberration. Wrapped in a lightweight carbon fiber tube at just 14 pounds, this 5-inch APO refractor punches well above its price class—offering optical quality that rivals scopes costing twice as much.

Key Features

• HOYA FCD100 ED Glass – FPL-53 equivalent extra-low dispersion glass virtually eliminates false color, delivering true-to-life colors on planets, nebulae, and in long-exposure astrophotography
• Air-Spaced Triplet APO Design – Three-element optical system achieves 0.91 arcsecond resolution and diffraction-limited performance across the field
• Carbon Fiber Tube Construction – Cuts weight dramatically compared to aluminum-tube APOs and reduces thermal expansion for faster cool-down at dark-sky sites
• 2.5” Hexagonal Dual-Speed Focuser – Rock-solid rack-and-pinion design with 10:1 fine focus supports up to 10 lbs of imaging gear with zero image shift
• EMD Enhanced Multi-Layer Coatings – Maximizes light transmission and contrast for faint deep-sky targets
• Versatile f/7.5 Focal Ratio – Long enough for high-magnification planetary views, yet pairs beautifully with a 0.7x reducer for faster deep-sky imaging at f/5.25
• Retractable Carbon Fiber Dew Shield – Blocks stray light and slows dew formation during extended sessions
• 99% Reflective 2” Diagonal Included – Premium dielectric diagonal maximizes light throughput right out of the box

Ideal For

• Serious visual observers stepping up from doublets or entry-level triplets who want pinpoint stars, jet-black backgrounds, and zero false color on planets and double stars
• Astrophotographers who need tight, round stars across the field and a focuser that won’t flex under the weight of a dedicated astronomy camera, filter wheel, and auto-guider
• Traveling astronomers who haul gear to dark-sky sites—the 14 lb carbon fiber OTA is one of the lightest 5-inch APOs available, and the fast thermal equilibrium means less time waiting and more time observing
• Upgraders from 80–102mm APOs looking for a meaningful jump in aperture and resolution without needing a heavier mount

Accessories & Compatibility

• Explore Scientific 3” Field Flattener & 0.7x Focal Reducer – Corrects field curvature and reduces focal length to f/5.25 for faster deep-sky imaging with sharp, flat stars edge-to-edge
• Explore Scientific 8x50 Illuminated Right Angle Polar Finder – Accurate polar alignment with an illuminated reticle for precise tracking
• Explore Scientific EXOS2-GT Equatorial Mount – GoTo motorized mount with automatic object tracking for long-exposure astrophotography
• Explore Scientific Soft-Sided Telescope Case – Padded protection for transport to dark-sky sites

Note: A finder scope and carrying case are not included. The pre-installed hybrid finder base accepts most standard finder scopes and guiding systems.