Explore Scientific ED102 Essential Series Air-Spaced Triplet APO Refractor Telescope
- 102mm Aperture
- f/7 Focal Ratio
- Air-Spaced Triplet Apochromatic Optics
- Genuine HOYA FCD1 ED Glass
- 2" Rack-and-Pinion Focuser
See exactly how your targets fit with the Explore Scientific ED102 Essential Series Air-Spaced Triplet APO Refractor Telescope, on real sky survey data.
Launch Imaging Assistant
See exactly what the Explore Scientific ED102 Essential Series Air-Spaced Triplet APO Refractor Telescope shows you, on real sky survey data.
Launch Visual AssistantThe Explore Scientific ED102 Essential Series Refractor combines a 102mm aperture with an f/7 focal ratio in a true apochromatic, air-spaced triplet design for color-free, high-contrast views. Its genuine HOYA FCD1 glass element virtually eliminates chromatic aberration, delivering pristine images to the robust 2-inch rack-and-pinion focuser.
At the core of the ED102 is an air-spaced triplet objective lens featuring a genuine HOYA FCD1 extra-low dispersion glass element. This apochromatic design brings red, green, and blue wavelengths to a single, sharp focus, effectively eliminating the distracting purple fringing seen in simpler refractors. Views of bright targets like Jupiter's cloud bands, Saturn's rings, and the lunar terminator are rendered with stark, high-contrast detail against a black sky background, thanks to proprietary EMD multi-layer coatings that maximize light transmission.
Designed for both visual observers and astrophotographers, the ED102 includes a heavy-duty 2-inch rack-and-pinion focuser. This design provides the rigidity needed to support a full imaging train—including a DSLR or dedicated astronomy camera, filter wheel, and off-axis guider—without flexure or image shift. The large 2-inch barrel accepts wide-field eyepieces for expansive views and provides an unvignetted light path for larger camera sensors, while included extension tubes ensure you can reach focus with a variety of accessories.
A common decision for refractor buyers is choosing between a two-lens ED doublet and a three-lens apochromatic triplet like the ED102. While an ED doublet offers good color correction, the triplet design provides a superior level of performance, particularly for imaging.
For visual use, a stable alt-azimuth mount like an Explore Scientific Twilight I or a Vixen Porta II is sufficient. For long-exposure astrophotography, a German equatorial mount with GoTo capability, such as an Explore Scientific EXOS2-GT, Celestron AVX, or Sky-Watcher HEQ5, is required to handle the telescope's weight and provide accurate tracking.
Yes, absolutely. The ED102's apochromatic optics deliver the high-contrast, color-pure images needed to capture fine details on planets. When paired with a high-speed planetary camera and a 2x or 3x Barlow lens, you can resolve features like the Great Red Spot on Jupiter, cloud bands on Saturn, and polar caps on Mars.
The 102mm aperture gathers significant light for deep-sky observing and imaging. On the Orion Nebula (M42), you will be able to resolve the four main stars of the Trapezium cluster set against detailed nebulosity. For imaging, the f/7 focal ratio is fast enough to capture the nebula's faint outer structures with moderate exposure times, while the triplet optics ensure the bright core stars remain sharp and color-correct.
HOYA FCD1 is a high-grade, extra-low dispersion (ED) glass. Its specific optical properties allow it to bend different colors of light at very similar angles. When used as the central element in the ED102's triplet lens, it dramatically reduces chromatic aberration, resulting in sharper, higher-contrast images without false color.
Yes. The Explore Scientific ED102 comes standard with a 2-inch focuser. This allows you to use 2-inch diagonals and wide-field eyepieces for sweeping, low-power views of large objects like the Andromeda Galaxy (M31) or the Pleiades (M45). It also ensures a wide, unvignetted illumination field for astrophotography with larger sensors.
An "air-spaced triplet" refers to an objective lens made of three separate glass elements separated by a thin cushion of air. This design gives optical engineers more variables to work with compared to a cemented or oil-spaced lens, allowing for a higher degree of correction for optical aberrations like chromatic aberration and spherical aberration.
| Aperture | 102mm |
| Focal Ratio | f/7 |
| Optical Design | Air-Spaced Triplet Apochromat |
| ED Glass Type | HOYA FCD1 |
| Coatings | EMD (Enhanced Multilayer Deposition) |
| Focuser | 2" Rack-and-Pinion |
| GTIN | 8122570149582 |
ED102 Essential Series Optical Tube Assembly
× 1
Focuser Extension Tubes
× 1 set