Explore Scientific ED80-FCD100 80mm f/6 Air-Spaced Triplet Refractor with 0.8x Focal Reducer

Product Overview

The Explore Scientific ED80-FCD100 is an 80 mm f/6 air-spaced apochromatic triplet refractor using HOYA FCD-100 extra-low-dispersion glass, the higher grade in Explore Scientific's ED line. Focal length is 480 mm and the tube assembly weighs 7.5 lb. This configuration includes the Explore Scientific 0.8x focal reducer, which brings the working system to f/4.8 for wide-field imaging.

Who It's For

This suits an imager who wants the strongest colour correction available in a compact 80 mm tube, and an observer who values a clean, halo-free view on the Moon, planets, and bright double stars. Compared with the Essential Series version of the same optical layout, the FCD-100 glass reduces residual colour further; it is the choice when the telescope will be doing serious long-exposure work rather than occasional imaging.

Key Features & Design

• HOYA FCD-100 ED glass in an air-spaced triplet objective — Explore Scientific's premium ED substrate
• Included 0.8x focal reducer yields an f/4.8 imaging system
• 2.5-inch hexagonal rack-and-pinion focuser rated for 10 lb of imaging equipment
• 99% reflective 2-inch dielectric diagonal included for visual use
• Two focuser extension tubes to reach focus with varied eyepiece and camera trains
• Retractable dew shield and Hybrid 2N1 finder base fitted to the tube

Optical and Mechanical Design

Three air-spaced elements, one of them FCD-100 ED glass, hold chromatic aberration low enough that bright stars record as points rather than as blue-fringed discs. Resolution is 1.45 arcseconds and limiting magnitude is 12. The tube is 18.5 inches long with the dew shield out and 15 inches retracted, 85 mm in diameter, on a Vixen-style dovetail. At 7.5 lb it is heavier than the Essential Series tube, which is worth accounting for when sizing a mount.

Recommended Uses

• Long-exposure deep-sky imaging of nebulae, galaxies, and clusters at f/4.8
• High-contrast visual observing of the Moon, planets, and double stars
• Narrowband imaging, where the flat, well-corrected field pays off across the frame
• Portable dark-site setups that still need apochromatic performance

Compatibility and Accessory Notes

The Vixen-style dovetail fits standard Vixen saddles, including the Explore Scientific iEXOS-100-2 and EXOS-2GT. The reducer presents a 42 mm T2 thread on the camera side, so add the T2 camera ring that matches your body; its barrel also takes standard 2-inch filters. The Hybrid 2N1 base accepts an Explore Scientific finder scope, sold separately.

Good to Know Before You Order

This is an optical tube with a reducer — mount, tripod, eyepieces, and finder scope are separate purchases. Explore Scientific publishes a 7.5 lb tube weight; the checkout shipping weight is rounded up to the next whole pound and does not alter the specification. Explore Scientific does not publish a separate weight for the reducer, so the shipping figure covers the tube and packaging.

Frequently Asked Questions

Is it difficult to set up? No. The dovetail seats in a Vixen saddle, the dew shield pulls out by hand, and the reducer threads on with the supplied adapter. Nothing requires collimation.

How is this different from the ED80 Essential Series? Same 80 mm f/6 triplet geometry; this one uses FCD-100 glass instead of FCD-1 and weighs 7.5 lb rather than 5.95 lb. The FCD-100 gives a further reduction in residual colour.

Do I still get a full-aperture visual setup? Yes. Fit the included 2-inch diagonal and an eyepiece; remove it and thread on the reducer when you want to image.

What size mount should I plan for? Something rated well above 7.5 lb once a camera or diagonal and eyepiece are added. The iEXOS-100-2 handles it for imaging.

Bottom Line

Explore Scientific's best 80 mm ED glass, with the 0.8x reducer already included so the telescope arrives ready to image at f/4.8. A compact apochromat that does not compromise on colour correction. Talk to our team in Bolton if you would like help pairing it with a mount.