Explore Scientific · Apochromat Refractor
Explore Scientific ED102 Essential Series Air-Spaced Apochromatic 102mm Triplet
Sharp, color-accurate views from a portable 102mm triplet apochromat, built for both visual observing and astrophotography.
Price updated Mar 22, 2026
Performance Scores
Overview
The Explore Scientific ED102 Essential Series is a 102mm air-spaced triplet apochromat with a 714mm focal length at f/7. That combination puts it in a genuinely useful middle ground: wide enough for deep-sky targets like nebulae and open clusters, while the tight chromatic aberration correction makes planetary detail look clean and contrasty. The FCD1 HOYA ED glass is the same type used in higher-end optics, and the air-spaced triplet design handles color fringing more effectively than doublets at this aperture.
At f/7, it pairs well with most camera sensors without requiring a field flattener on every target, though serious astrophotographers may still want one for full-frame work. The rack-and-pinion focuser is functional but worth noting if you plan to hang heavier camera rigs on it. At 5.44kg, the tube is manageable and the retractable dew shield helps keep setup time short.
The push-pull collimation adjustments on the front cell are a practical touch that many refractors in this price range omit. At $1,099, this sits in competitive territory for a triplet apochromat, and having US-based support removes some of the risk.
At a Glance
102mm
Aperture
f/7
Focal Ratio
5.44kg
Weight
Specifications
Key Features
- 102mm air-spaced triplet design using FCD1 HOYA ED glass keeps chromatic aberration tightly controlled across visual and photographic use
- f/7 focal ratio works with a wide range of eyepieces and camera sensors without extreme accessories
- Retractable dew shield and built-in cradle handle make setup and transport noticeably faster in the field
- Push-pull front cell collimation allows precise optical alignment, an uncommon feature at this price point
- Suitable for imaging the Moon, planets, and bright deep-sky objects without a dedicated astrograph setup
- Rack-and-pinion focuser is adequate for visual use but may feel limiting with heavier camera equipment
- US-based customer support provides a reliable resource if issues arise after purchase
Customer Reviews
12 reviews
This scope was my first step up from a Celestron 5SE I have which I've used for visual and tried for some astrophotography and I learned fast the SEs have limitations. I started with a Celestron AVX mount but have since switched to a ZWO AM3 mount along with all of the other ZWO equipment, camera, f...
I have several types of scopes. Several of those are refractor telescopes. This triplet is not the best on the market, however for the price this thing is exactly what you want. I have absolutely no chromatic aberration in stars and moon. The galaxies are crisp, the nebulas have full color range ins...
I bought the ES 102 triplet apo primarily for a planned venture into astrophotography with the thought of eventually purchasing a larger scope. I also wanted the experience of enjoying some visual observations. I have a lifetime of photographic experience but zero with telescopes. I wanted a high qu...