Assessment of Baader Hyperion Eyepieces: User Perspectives and Experiences
Revamped Guide on Baader's Hyperion Eyepieces
Grabbing a Baader's Hyperion eyepiece is an excellent decision if you're searching for quality, budget-friendly wide-field options. These eyepieces fit both 1.25" and 2" focusers without the need for adapters, offering a perfect fit for those with astigmatism or requiring long eye relief.
Eyepiece Lineup
The Hyperion series boasts several focal lengths, including:
- 24mm (slightly different optical design)
- 21mm
- 17mm (highly recommended)
- 13mm
- 10mm
- 8mm
- 5mm (great for planetary viewing)
The 3.5mm once existed, but it was discontinued since its demand was low and only useful with small refractors at moderate focal ratios.
Key Specifications
- Eye relief: 20mm (17mm with 24mm Hyperion)
- Apparent field of view: 68 degrees (61 degrees with 21mm Hyperion)
- Weight: 11.6-14.7 ounces (328-417 grams)
- Coatings: Baader's exceptional Phantom Group multi-coatings for reduced light loss and scattering
Focal Lengths Worth Considering
If your telescope boasts a focal ratio below f/6, especially a Newtonian reflector, avoid Hyperions. However, you might attempt the 5mm, and the 17mm might work alright if a coma corrector is at your disposal.
Users of longer focal ratio refractors or catadioptric telescopes should start by procuring the 17mm Hyperion, an impressive eyepiece that complements various users driving a moderate-to-low power eyepiece without replacing it. Despite already owning a 25mm Plossl eyepiece, or similar, the 17mm Hyperion makes a nice addition that enhances your viewing experience without completely replacing your existing equipment.
The 5mm Hyperion excels as a planetary eyepiece, but be cautious as it is near the maximum magnification an f/10 Schmidt-Cassegrain can handle, and exceeds the maximum magnification for longer focal length Maksutovs. If you're working with an SCT, opt for the 8mm instead, as it offers a more sensible magnification choice, despite its performance slightly inferior to the 5mm.
After the 8mm, consider getting the 13mm, 10mm, and 5mm in that order if they aren't already part of your collection.
The 21mm Falls Short
The 21mm Hyperion doesn't fill a useful niche and has limited appeal. As the review progresses, I'll explain why the 24mm Hyperion is also dubious.
Convenient Additional Features
The Hyperions all come with extra-large eye lenses and long eye relief, making them perfect choices for those with astigmatism and eyeglass wearers.
The unique optical design allows for the insertion of 'fine-tuning' rings between the upper and lower lens groups on all but the 24mm eyepiece. Fine-tuning rings shorten the focal length and increase spacing between the lens groups, a handy feature—however, they're costly. Investing in fine-tuning rings may be an unnecessary burden for inexperienced users, as making adjustments in the dark could potentially result in dust or dirt getting inside the eyepiece.
Removing the lower lens group entirely from standard Hyperions for 2" wide-field use doesn't yield desirable results, resulting in aberrations and almost useless eyepieces. I strongly advise against attempting this modification.
The Hyperions' removable eyecups expose M43 threads, which, when paired with a camera adapter, open the door to afocal photography. However, this option has limited appeal in the realm of serious astrophotography, and buying such gear is not worth the considerable investment.
Performance Assessment
Hyperions provide relatively affordable wide-field viewing, mainly suited for high-focal-ratio telescopes. They'll shine at f/15 or f/10 and do okay down to f/6. However, below f/6, the edge-of-field sharpness begins to falter, with edge-of-field astigmatism becoming apparent, typical of less expensive wide-field eyepieces.
The 21mm, 17mm, 13mm, 10mm, and 8mm Hyperions reveal noticeable "pin-cushion" distortion (field curvature) in low focal ratio scopes, which is unsettling.
The 24mm Hyperion Troubles
The 24mm Hyperion boasts the least field curvature among the family but lacks off-axis performance, even with relatively slow instruments. Majority of amateur astronomers despise it, including myself. Additionally, I cannot benefit from the fine-tuning rings with the 24mm, unlike other Hyperions.
The 21mm Offers Hope
The 21mm Hyperion, on the other hand, is excellent, with surprisingly good performance in fast scopes, though the smaller apparent field is a limiting factor. If you can manage the restricted field of view compared to other Hyperions, I highly recommend the 21mm.
The 17mm Eclipses the Competition
The 17mm Hyperion, commonly hailed as the best eyepiece in the series, provides stellar performance akin to the 17.3mm TeleVue Delos, albeit not quite living up to that model's reputation. The 17mm's field stop is the most defined of the Hyperion eyepieces, delivering the best off-axis sharpness.
Verdict on the Hyperions
Regardless of your telescope's focal length, the Hyperion eyepieces in 24mm, 13mm, and 8mm offer a well-balanced setup for a diverse range of observing. Adding a 17mm or 5mm further bolsters flexibility. Keep in mind that your telescope's focal length is crucial when selecting eyepieces to work with your targeted objects.
- The Hyperion series of eyepieces, including the 24mm, 21mm, 17mm, 13mm, 10mm, 8mm, and 5mm, cater to a variety of telescopes and offer a perfect fit for those with astigmatism or requiring long eye relief.
- For telescopes with a focal ratio below f/6, especially Newtonian reflectors, the 5mm and 17mm Hyperions might work well, especially with a coma corrector for the 5mm.
- Users of longer focal ratio refractors or catadioptric telescopes should start with the 17mm Hyperion, as it delivers impressive wide-field viewing without replacing their existing eyepieces.
- The 5mm Hyperion is a high-performing planetary eyepiece, but it may exceed the maximum magnification for longer focal length Maksutovs, and for SCT, it's recommended to use the 8mm instead.
