Baader’s Hyperion line was introduced in the mid-2000s to provide quality, relatively inexpensive wide-field eyepieces that fit both 1.25” and 2” focusers without the use of adapters. They are particularly well-suited for those with astigmatism or who otherwise require a long eye relief.
Available Focal Lengths: 24mm, 21mm, 17mm, 13mm, 10mm, 8mm, and 5mm. The 24mm uses a slightly different optical design than the other six. A 3.5mm was once made, but it was discontinued due to a lack of demand at that focal length for such an eyepiece; it was really only useful with small refractors at moderate f/ratios.
- Eye Relief: 20mm (only 17mm with 24mm Hyperion)
- Apparent field of view: 68 degrees (61 degrees with 21mm Hyperion)
- Weight: Between 11.6-14.7 ounces (328-417 grams)
- Coatings: Baader’s Phantom Group multi-coatings for minimal light loss and scattering
Focal Lengths That I’d Recommend
I would recommend steering clear of the Hyperions if you use a telescope with a focal ratio below f/6, particularly a Newtonian reflector telescope. However, you might still give the 5mm a shot, and the 17mm should work alright if you have a coma corrector handy.
If you’re using a longer focal ratio refractor or catadioptric, I would recommend obtaining the 17mm Hyperion first. I consider it the best in the line and a good moderate-to-low-power eyepiece for most users. Even if you’ve already got a 25mm Plossl eyepiece or the like with your scope, the 17mm Hyperion would complement it nicely without replacing it. These eyepieces are definitely an improvement on the inexpensive Plossls, Kellners, and most wide-field eyepieces that come with budget telescopes, and maybe all you ever need.
The 5mm Hyperion is a great planetary eyepiece, but it’s at about the maximum magnification an f/10 Schmidt-Cassegrain can handle and exceeds the maximum magnification a longer focal length Maksutov can manage. The 8mm Hyperion is probably better-suited for high power with an SCT, even if its performance is slightly inferior, as it offers a more sane magnification choice.
After that, I would recommend obtaining the 13mm, 10mm, and 8mm in that order if you haven’t already.
To me, the 21mm doesn’t fill enough of a useful niche, and as I’ll explain later in the review, I do not recommend the 24mm Hyperion for any telescope due to the lack of sharpness.
Baader also offers a Hyperion Zoom, which is similar in name only, and two “Hyperion Aspheric” eyepieces with 72-degree fields at 31mm and 36mm focal lengths. The Hyperion Aspherics are native 2” format and really designed to be used as 2” eyepieces only, as they will vignette with the included 1.25” adapters (particularly the 36mm). They share little in common with the standard Hyperions, and as such, they will not be discussed further in this review.
Analyzing the Features
The Hyperions all have very large eye lenses and long eye relief, which to me makes them ideal for those who have astigmatism and must wear eyeglasses.
In addition, the Hyperions’ unique optical design allows for the insertion of ‘fine tuning rings’ between the upper and lower lens groups on all but the 24mm eyepiece. The fine tuning rings shorten the focal length of the eyepieces simply by increasing the spacing between the lens groups. However, the tuning rings are costly, and for inexperienced users, changing them in the dark would be a worrying process that might leave dust/dirt inside their eyepiece. Therefore, I’d recommend using the eyepieces simply at their fixed focal lengths and not bothering to fool around with the fine tuning rings.
While Baader claims you can remove the lower lens group entirely from the standard Hyperions to use them as 2” wide-field eyepieces, doing so results in a rather aberration-filled eyepiece with almost no eye relief, rendering the eyepiece almost useless. I strongly advise against trying it.
The Hyperions’ eyecups are removable, exposing M43 threads. You can buy a camera adapter and shoot afocally through the eyepiece if you want to. But there is little advantage in shooting afocally anymore for serious astrophotography, and I would not recommend spending hundreds of dollars on gear to do so.
The Performance Comparison
The Hyperions are relatively inexpensive wide-field eyepieces. Due to their low prices and the design requirement of large eye lenses and long eye relief, which I believe limits other aspects of the optical design, they are really meant only for high-focal-ratio telescopes.
Hyperions will do great at f/15 or f/10, and okay down to f/6. But below f/6, I’ve noticed that the edge-of-field sharpness of the views begins to fall off, with the eyepieces displaying the edge-of-field astigmatism all-too-typical of less expensive wide-field eyepieces.
The 21mm, 17mm, 13mm, 10mm, and 8mm Hyperions exhibit noticeable “pin-cushion” distortion (field curvature) in low focal ratio scopes, which often bothers me.
- 24mm Hyperion
The 24mm has probably the least field curvature of any of the Hyperions—I’d thank the different optical design for that. But it also has the worst off-axis performance, even with relatively slow instruments. The majority of amateur astronomers strongly dislike it, including myself. Additionally, I cannot take advantage of Baader’s fine tuning rings with the 24mm, unlike with the other Hyperions. Overall, I would not recommend the 24mm Hyperion for use with any telescope.
- 21mm Hyperion
The 21mm Hyperion, on the other hand, is excellent. But my testing revealed that the field of view on it is actually about 61.5 degrees, not the 65 that Baader claims. Baader’s restriction of the outer 3.5 degrees of the field definitely cleans up the edge sharpness (even though it is simply masking the problem, not removing it outright). Performance in fast scopes is surprisingly decent, though again, it’s unfairly boosted by the smaller apparent field. If you’re able to live with the restricted field of view compared to the other Hyperions, I highly recommend the 21mm.
- 17mm Hyperion
The 17mm Hyperion is largely regarded as the best eyepiece in the set, with some calling it a “poor man’s 17.3mm TeleVue Delos,” as it has a similar field of view, focal length, and nearly as good performance as said eyepiece (However, I regard the 17.3mm Delos as one of the weaker eyepieces in its family). The field stop is the most well-defined of any of the Hyperion eyepieces, and the 17mm has the best off-axis sharpness.
- 13mm Hyperion
The 13mm Hyperion has very good performance in slow instruments of f/8 or above, but the worst performance at even moderately fast focal ratios. I found it to be a very good fit for my 8” SCT, but it is probably not a good choice for most Newtonians or moderately fast refractors.
- 10mm, 8mm, 3.5mm Hyperions
The 10mm, 8mm, and 3.5mm Hyperions have more or less the same performance: not amazing in fast scopes, pretty good at f/6 and above, and spectacular in catadioptrics and refractors at f/10 or above. The 5mm Hyperion seems to have slightly less field curvature and off-axis aberrations than the other <13mm Baaders, and you could potentially get away with using it in a fast Newtonian.
Thanks for the review,I’m a very amateur beginner.ive got a nexstar evolution 5,from what you have said ,these eyepieces will be good.
excellent review and thanks
I’m looking to add the 8, 10 and 13….to my Celestron Evolution 6 f/10
Where would you rate these eyepieces to the Celestron X-cel and the Luminos?
Really different use cases. The Luminos eyepieces have some edge of field brightening issues but have a wider AFOV. The X-Cels are on par in sharpness but cheaper and narrower field.
Hugely thorough review! Thank you, this has probably saved me from buying one as I have a Newtonian.
Hi, I’m new to astronomy and have just purchased a Discovery 150P.
You don’t seem to recommend these for f5 reflectors.
What brand/type eyepieces would you recommend & why?
Thanks
The correction of the Hyperions isn’t great with fast scopes and they have a lot of edge-of-field astigmatism. The Explore Scientific 68 or 82-degrees, or Meade UWA eyepieces, have better correction for fast scopes.
For a 8 inch f/6 newtonian ,which would be the best branded eyepieces for high power(5 mm) and moderate power (10 mm) .
Is it better to invest in a separate 5 mm wide angle eyepiece or barlow a 10 mm piece
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