Baader 31mm Hyperion Aspheric 2" Eyepiece

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Baader 31mm Hyperion Aspheric 2" Eyepiece

# 2454631

€ 195.00 Price excl. German VAT tax (19%): € 163.87

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  • Fixed focal length of 31mm Hyperion Aspheric 2" Eyepiece, 72° extreme widefield for large field of view
  • High quality Phantom Group Coating for maximum contrast
  • DSLR camera adaptable as projection eyepiece, with system thread SP 54

Product Questions and Answers

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Is the 72° available with the 31,75mm plug-in sleeve?
Question by: MARIE on Sep 15, 2017 2:30:00 PM | 1 Answer(s)

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Will the Hyperion 31mm eyepiece be useful with my dobsonian 16" f/4,5 reflector? How much edge of field distortion will there be?
Question by: Joachim Mikkelsen on Jan 17, 2021 6:05:00 AM | 1 Answer(s)

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Do you confirm the 72° apparent field of view with 31,75 mm connexion?
Question by: Eric MARIE on Mar 6, 2017 9:10:00 AM | 1 Answer(s)

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Bought this eyepiece a couple of months ago and noticed some debris (dark specs) on the inside of the eyepiece. I've used a blower to the top and bottom lenses and the debris remains visible. Any idea how to fix this problem? My understanding is that Baader is a synonym of quality. I hope this is a one time case.
Question by: Marco on Jun 24, 2023 3:19:00 PM | 1 Answer(s)

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Which adapter ring i need to fit ASI 120mc ZWO on hyperion eyepiece 21mm.
Question by: bernard Goudreault on Aug 30, 2018 8:23:00 AM | 1 Answer(s)

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Can I attach the 2.25 barlow to this eyepiece?
I have T-2 Adapter #2956180B, Adapter #2956180A and Hyperion Zoom Barlow 2.25x.
What exactly do I need to attach? Do I need an extra attachment?
Question by: Emilio Lavignasse on Dec 19, 2020 11:36:00 PM | 1 Answer(s)

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Is this eyepiece compatible with a F=1000mm, D=200mm telescope?
Thanks in advance for the answer
Question by: Arnaud Haemmerle on Dec 30, 2016 10:14:00 AM | 1 Answer(s)

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Aspherical Eyepiece with 31mm and 36mm focal length (with Phantom Coating® Group)

Aspherical Eyepiece:

Normally, near-the-edge, rays are refracted towards the center when passing a lens, as near-axis light beams. Therefore, the image field in an uncorrected system can become blurred to the edge. The aspherical correction of an optical system, as with these eyepieces, now resolves numerous imaging errors at once. The sharpness is achieved over the entire image field, the distortion is reduced to a minimum and the eyepiece can be made much smaller and lighter.

The eyepieces are each delivered with 1¼ "and 2" plug-in sleeves

Application of Baader 2" Aspheric eyepieces

Asphercial Eyepiece
Aspherical Nexstar

Aspheric 2" eyepieces are launched against the world's most powerful large-field eyepieces and offer compelling advantages: higher star-limit size, unsurpassed color accuracy, low weight and an attractive price.

The aspheric eyepiece design includes aspheric lens surfaces as they are now the standard in the most modern camera lenses to offer the best image performance over the entire image field. The Aspheric eyepiece construction allows for fewer glass surfaces and in combination with the extreme quality of the Phantom Group multi-device. An Aspheric eyepiece delivers a brighter, more contrast-rich image than even expensive expensive wide-angle eyepieces with spherical lenses.

The Aspheric face is 72 degrees only minimally larger than the largest viewing angle of the human eye (68 degrees). In this way, the entire star field can be surveyed at once without having to "roll" with the eyes. Many wide-angle eyepieces offer an impressive 80-degree field of vision and more, but they can not be overlooked at all and the available light is distributed over an area of too large, so that the image brightness (= star limit) and contrast are given away.

The larger the image angle of a wide-angle eyepiece is constructed, the more difficult it becomes for the ocular designer to produce a good insight.

Extreme wide-angle eyepieces, but also wide-angle eyepieces with simple lens construction, often have a very "nervous" insight. If the eye is moved back and forth only slightly, the image field has disappeared immediately. A nervous eyepiece is a frustrating experience, especially for working with students, guests or at the people's day, because the observer obtain a good obervation.

In a direct comparison, all observers find that an Aspheric eyepiece exhibits finer stars and weaker structures in gas nebulies than much more expensive 2" wide angle eyepieces. Technological progress is particularly dramatic here.

Photographic adapter threads for all types of projection photography:

Photographic adapter threads for all types of projection photography
Photographic adapter threads for all types of projection photography

Photographically, all conventional DSLR camera housings can be attached directly behind the eyepiece using the eye-side M43 or the SP 54 system lens. A huge selection of adapter threads and transition rings are available. Thus, the telescopic focal length can be changed almost arbitrarily if small star fields or planetary objects are to be documented with high resolution. A detailed guide is included with each eyepiece.

System suitability for projection photography:

Photographic adapter threads for all types of projection photography
Afocal Projection Photography with Baader Aspheric Eyepieces

Each Aspheric eyepiece is equipped with screw threads on both sides in order to be able to install it as a projection system in an optical beam path.

On the telescope side there is a 2" SC thread in the eyepiece body which allows the eyepieces to be screwed firmly to the end of the tube of all Schmidt Cassegrain optics without a plug-in sleeve and without a zenith mirror.

Visually, this extremely short attachment allows for a larger true field of view than any wide-angle eyepiece with 2" plug-in sleeve.

Two-eyed stereoscopic observation with Aspheric eyepieces:

Stereoscopic observation with Aspheric eyepieces
Stereoscopic observation with Aspheric eyepieces

Aspheric eyepieces are the only long-focal wide-angle 2" eyepieces that can also be attached to astro-binoculars on both sides of the eyepiece. The Aspheric Eyepiece can be placed in any telescopic binocular, with the minimum eye distance not less than 56mm.

Baader Phantom Coating® Group

Baader Phantom Group Coating is a 7-ply broadband reflective coating with extremely low residual reflection. The term "group" indicates that the most effective anti-reflective layer system has been calculated for each individual glass group of the lenses used in the Hyperion eyepieces.

All these different anti-reflective layers on each individual glass surface have been optimized so that they are most effective where the human eye has its highest after-sensitivity - at approx. 520 nm - in the green area of the spectrum.

The best anti-reflective coating appears almost colourless: this proves that the anti-reflective coating is equally effective over the entire visible spectrum. Phantom Group anti-reflection coatings are almost completely colorless, depending on the type of glass. In this way it is ensured that the least light is lost for the night-adapted eye and that no stray light can occur.

If a tempered lens (eyepiece or lens) shows a strong green reflex when viewed from the front, this is not a Baader Phantom Group anti-reflection coating! The intense green reflex is a sign of a low-cost coating technique and means that most of the light is reflected in the spectral range between 500-550 nm, that is, lost.


Furhter information, image results...

Baader Blogpost:
The eyepiece series from Baader Planetarium

Baader Blogpost:
The camera at the eyepiece

Baader Blogpost:
Barlow lenses, their magnification factors and working distances

Related Articles

Additional Information

Manufacturer Baader Planetarium
SKU (#) 2454631
EAN Code 4047825011404
Net weight (kg) 0.40
Eyepiece Series Hyperion
Focal Length 31 mm
Apparent Field of View 72°
Eye Relief (mm) 17 mm
AR-Coating Phantom Coating® Group
Parfocal Eyepieces Yes
Barrel Size (in) 1¼", 2"
Optical Design Aspheric
Speciality Eyepiece projection: classical
Eyepiece Design
Field Stop Diameter 38 mm (2"), 30mm (1¼")
Field Stop Displacement to reference plane +/- 0 mm
Number of Lens Elements 6
Number of Groups 4
Slip Protect Safety Classic Undercut
Eyepiece Body above Reference Plane (mm) 76,7 mm
Length of 1¼" barrel (mm) 23,9 mm
Length of 2" barrel (mm) 27,5 mm
Outer Diameter 59,5 mm
Camera Thread M43, SP54
Threaded for filters Yes
Included Items
Dustcaps 1¼" dustcap (31,8mm), 2" dustcap (45mm), 2" dustcap (46.5mm - fits over eyecup)
Eyecups folding eyecup (M43)

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6 Item(s)

Marco 55/02/2024 25/02/202410:02
  • Rating:
Super Okular
Mir hat für mein 203/1200 Newton noch ein Übersichtsokular gefehlt. Das 31mm Okular hat bei mir eine Vergrößerung von 38x. Perfekt um einen Überblick am Himmel zu bekommen. Das Gesichtsfeld ist wunderbar groß, das Einblickverhalten ist sehr angenehm. Die Qualität ist hervorragend. Das Okular macht einen sehr wertigen und massiven Eindruck. Für das Geld bekommt man nichts besseres. Ich würde die Hyperion Okulare jedem empfehlen.
  • Qualität, Preis/Leistung
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C. Evangelista 112/04/2022 23/04/202219:01
  • Rating:
Hyp 31 auch als modulares Okular mit Barlow
Ich habe erst später bemerkt, dass das Okular auch modular einsetzbar ist:
z. B. mit zugehörigem 1,25"-Adapter und einer sehr guter Barlow 2x erhält man die Brennweite von 15,5 mm. Hier wird das Okular richtig gut: nachdem ich mit dieser Kombi z. B. gamma Vir im LZOS 130/780 trennen konnte (was mir mit einem TeleVue Plössl 15 mm nicht gelang), habe ich das TeleVue verkauft. Also, sehr viele gute Möglichkeiten mit dem Hyp 31...
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C. Evangelista 122/05/2022 03/05/202200:46
  • Rating:
Sehr gute Transmission; bei f/6 nicht mehr randscharf
WA-Okular mit hervorragender Transmission.
Am 5" f/6 Triplet Apo nicht mehr randscharf, im Zentralbereich jedoch sehr gut.
Gute Haptik und sehr leicht für ein 2" WA.
Preis-/Leisungs-Verhältnis stimmen.
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Toby Baier 236/08/2021 25/08/202112:30
  • Rating:
Bestes Okular!
Dies ist das beste Okular durch das ich jemals schauen durfte, Punkt, nein, Ausrufezeichen! Super klar, super scharf, toller Blinkwinkel, einfach eine Freude!
  • Bildqualität
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UweP 334/12/2018 01/12/201809:28
  • Rating:
sehr gutes Okular
Mir gefällt das Okular sehr gut. Das Bild ist scharf und der Augenabstand angenehm. Die Fertigungsqualität ist wie für alle Hyperion-Okulare makellos. Es macht Spaß, mit ihm am Himmel "spazieren zu gehen".
Dank der Anschlussgewinde lässt sich Kameratechnik sicher und schnell anbringen und auch die Möglichkeit, statt der 2-Zoll-Hülse eine 1,25-Zoll-Hülse einzuschrauben, finde ich praktisch.
  • großes Gesichtsfeld, angenehmes Beobachten
  • -
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James 324/11/2017 21/11/201705:36
  • Rating:
Outstanding Wide Angle Eyepiece
I like this eyepiece for the crisp, distortion-free, wide angle views that it provides, but in addition, it is less than half the weight of 82 degree eyepieces of equivalent focal length and it has good eye relief too. I use it in a 60 mm APO refractor telescope, where it yields a seven degree field of view, wide enough to frame the Hyades Cluster.

Very fine optical design and exquisite workmanship! Thanks, Team Baader.
  • Distortion-free, wide angle views, excellent eye relief, light weight
  • Nothing
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