Explore Scientific · Apochromat Refractor
Explore Scientific ED127 FCD100
127mm of apochromatic clarity in a carbon fiber package, built for serious visual and imaging work.
Price updated Mar 22, 2026
Performance Scores
Overview
The Explore Scientific ED127 FCD100 is a 127mm f/7.5 air-spaced triplet apochromat that uses FCD100 extra-low dispersion glass to control chromatic aberration to a degree that simpler doublets or standard ED scopes cannot match. At 952mm focal length, it sits in a useful middle ground: long enough for detailed planetary views and tight enough for wide deep-sky fields with the right eyepieces.
The carbon fiber tube keeps weight manageable at just over 9.5kg while resisting thermal expansion during cool-down, which helps maintain focus stability across a long observing session. The 2.5-inch hexagonal focuser handles heavy camera rigs without flexure, and the included 99% reflective diagonal is genuinely good, not an afterthought.
This scope performs well for visual observing on globular clusters, planetary nebulae, and double stars, and its flat, well-corrected field makes it a legitimate astrophotography instrument as long as you pair it with a solid equatorial mount. At this price point, the optics quality is the main argument for choosing it over cheaper alternatives, and Explore Scientific's reputation on that front is solid.
At a Glance
127mm
Aperture
f/7.5
Focal Ratio
9.53kg
Weight
952mm
Focal Length
Specifications
Key Features
- FCD100 triplet glass delivers sharp, color-accurate views with minimal chromatic fringing across a wide range of targets
- Carbon fiber tube reduces cool-down time and maintains focus stability as temperatures drop overnight
- 2.5-inch hexagonal focuser supports heavy cameras and accessories without introducing tilt or flex
- 952mm focal length at f/7.5 is versatile enough for both planetary detail and wide-field deep-sky work
- Included 99% reflective 2-inch diagonal is a quality component that does not need immediate replacement
- Cradle rings with handle and Vixen-style dovetail make mounting and balancing straightforward on most setups
- At 9.5kg, this scope requires a capable mount, plan for at least a mid-range equatorial to get the best out of it