Binorum Kellner eyepiece 10mm 50° 1.25″
Looking for a reliable eyepiece that delivers sharp, high-contrast views without unnecessary compromises? The Binorum Kellner 10mm eyepiece is exactly what you need. It is based on the proven Kellner optical design - a construction that has earned a solid place in the equipment of observers around the world over decades of astronomical practice. The 10mm focal length provides a comfortable medium magnification suitable for a wide range of astronomical objects, from details on the lunar surface to planetary discs.
Optical design and performance
The Kellner design is a three-element system made up of two achromatic lenses and one plano-convex lens. It is known for excellent correction of chromatic aberration while keeping the construction simple and robust.
The 50° apparent field of view is a very solid value for this class of eyepiece. The image stays sharp across almost the entire field, and contrast is high thanks to the low number of air-to-glass surfaces.
For technically minded observers: when used with a telescope of 1000mm focal length, the exit pupil will be 1.0mm (with a 100mm objective, this gives 100x magnification). This is an ideal setup for planetary observation under good atmospheric conditions.
Compatibility and versatility
The 1.25″ barrel diameter is the most widely used standard today, so this eyepiece fits the vast majority of refractors, reflectors, and catadioptric telescopes available on the market.
With its 10mm focal length, this eyepiece is a truly versatile tool. It handles detailed views of the Moon and planets just as well as observations of bright open clusters or globular clusters.
The Kellner optical design is also less sensitive to manufacturing tolerances than more complex constructions. This means that even at a friendly price point, you can expect consistent and reliable results every time.
Who is this eyepiece for?
This eyepiece suits a wide range of users:
- Beginning astronomers who are looking for affordable and reliable optics for their first eyepiece set
- Experienced observers who need a backup or travel eyepiece that can handle demanding field conditions
- Anyone who values simplicity - fewer optical surfaces mean fewer reflections, less light loss, and a cleaner image, especially when observing bright objects such as planets or the Moon
Technical specifications
| Parameter |
Value |
| Focal length |
10mm |
| Apparent field of view |
50° |
| Barrel diameter |
1.25″ |
| Optical design |
Kellner (3 elements) |
| Number of air-to-glass surfaces |
Low |
About Binorum
Binorum is a brand born from a passion for astronomy - created by astronomers for astronomers. Every product in the Binorum range goes through careful selection with a focus on optical quality, mechanical precision, and long-term reliability.
Binorum offers a wide range of astronomical accessories - from eyepieces of various designs and focal lengths to filters, finder scopes, and mounting accessories - so you can easily build a complete telescope setup from a single brand.
The brand's approach is calm and straightforward: no unnecessary marketing hype, just honest optics for those who are serious about astronomy.
