Baader Planetarium Hyperion 17mm 68° eyepiece 2″/1.25″
The Hyperion series from Baader Planetarium is one of the most popular eyepiece lines on the market - and for good reason. It is a favourite not only among beginners but especially among experienced observers who know exactly what they need from their equipment. The 17mm focal length model with a 68° apparent field of view offers a comfortable balance between detail and overview, making it equally useful for observing planets and larger deep-sky objects.
Optical design and image quality
The eyepiece is built around an 8-element optical design arranged in 5 groups. This construction delivers sharp, clean, neutral-white images across the entire field of view, without unpleasant colour fringing at the edges. The eye relief is a comfortable 20mm - consistent across all focal lengths in the Hyperion range. This is an important detail for eyeglass wearers, who will appreciate that they do not need to press the eyepiece close to the eye.
The FMC (Phase FMC) fully multicoated anti-reflection treatment minimises light loss and unwanted reflections, resulting in a contrasty and bright image even under challenging conditions. Excellent internal blackening of the barrel further eliminates stray light inside the eyepiece.
Modular design - two eyepieces in one
One of the most interesting features of the Hyperion series is its modular construction. By unscrewing the negative front element, the 17mm Hyperion becomes a full 6-element 2″ Erfle eyepiece with a significantly longer focal length - ideal for wide-field, low-magnification observing. This option greatly increases the practical value of the eyepiece and will be appreciated by anyone who enjoys experimenting with different telescope configurations.
The Baader Hyperion effectively offers two optical solutions in a single compact body.
Ready for astrophotography
Hyperion eyepieces are designed from the ground up for projection and afocal photography. At the exit end of the eyepiece you will find two threaded rings - M54 and M43 - which allow direct attachment of a camera or other accessories without the need for improvised adapters. Adapters are available for most common photographic thread standards, so compatibility is rarely an issue. Both threads are protected by rubber caps when not in use, preventing scratches and dust from getting in.
Build quality and attention to detail
Baader Planetarium is one of the most respected names in astronomical optics, and the Hyperion series reflects that reputation. Refined optics, modular design, solid mechanical construction, and careful attention to detail - such as the rubber thread caps and a fold-down rubber eyecup - make this eyepiece a reliable companion for night observing sessions and astrophotography alike.
If you are looking for an eyepiece that can handle more than one role and will serve you well for many years without any compromise in image quality, the Hyperion 17mm is a clear choice.
Key specifications
| Parameter |
Value |
| Focal length |
17mm |
| Apparent field of view |
68° |
| Eye relief |
20mm |
| Barrel diameter |
2″ / 1.25″ |
| Optical design |
8 elements in 5 groups |
| Coating |
Phase FMC (fully multicoated) |
| Modular Erfle configuration |
6 elements, 2″ barrel |
| Photography threads |
M54 and M43 |
