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Baader Hyperion 1.25"/2" Modular Eyepiece

Baader Hyperion 1.25''/2'' Modular Eyepiece
 Baader Hyperion 1.25''/2'' Modular EyepieceBaader Hyperion 1.25''/2'' Modular Eyepiece 
Price:  £119.00(Inc. 20% VAT)

Model:  2454605
Brand:  Baader

2 Year Warranty On All New Items
(Excluding Batteries & Globes)

  (4 Reviews)

High Quality 68 Degree Eyepiece

Modular dual 31.7mm/50.8mm widefield eyepieces that performs as well as eyepieces three times its price. Will work in conjunction with a Baader adaptor ring to mount a camera directly onto the eyepiece.

See below a video that shows Ian and Darren showing you the versatility when using these eyepieces with the fine tuning rings.

Characteristics for visual use:

Optimal 68° apparent field of view, the largest accessible to the stationary human eye.
The entire field remains visible despite the slight involuntary motions of an observer’s head that simply can’t be avoided.
The 80°+ apparent fields of many other eyepiece designs may sound very appealing on paper, but the need for the observer to slavishly maintain an eye position precisely on the optical axis is seldom if ever mentioned.
The annoying „kidney bean effect”, the bane of many ultra wide-field eyepiece designs, is completely absent in the Hyperion.
8 lens elements in 5 groups provide outstanding sharpness and color correction over the entire field.
Comfortable eye relief of 20 millimeters.
No vignetting or falloff of illumination near the edge of the field.

The use of high-index glasses results in minimal distortion and astigmatism.
Unsurpassed color fidelity. Many eyepieces that employ cheaper glasses or inferior designs impart a yellow or blue cast to the image.

With Hyperion eyepieces white stays white!

The most advanced anti-reflection multicoatings are employed on all ten air to glass surfaces for maximum light throughput and brilliant images.

All coatings are carefully matched to the index of refraction for each of the different glass substrates used.

The painstaking design and execution of baffling has all but eliminated troublesome stray light and ghost reflections. Don’t take our word for it – test it for yourself!

Put a Hyperion eyepiece and your own eyepieces onto a matte black surface and allow a beam of sunlight or an intense artificial light source to shine into the eyepieces from above. Looking into the eyepieces from some distance you will note that some eyepiece interiors will shine milky white with stray light, resulting in a „flat” image with reduced contrast. Not the Hyperion! Under all conditions of illumination, the interior of a Hyperion eyepiece will appear jet black, testimony to the virtual elimination of stray light.

Shortest field stop position of all widefield-eyepieces known to us.

Specifically designed for binocular viewing

Ideal for use with accessory binocular viewers thanks to a tight barrel diameter (58 millimeters with the removable neoprene rubber grip ring, 56 millimeters with the grip ring removed) that permits interpupillary distance settings of as little as 56 millimeters, permitting stereo wide views even for kids.

Each Hyperion eyepiece in the series is actually two eyepieces in one! Simply by unscrewing the forward 1.25-inch diameter portion of barrel that houses the negative achromat lens group, will provide a wide-field eyepiece of much longer focal length. Color correction remains excellent, and the field curvature that results is no greater than in a decent specimen of the 6-element Erfle design (and that’s what it is actually, when the negative achromat is removed).

Removing the negative lens group exposes an M 48 female thread at the end of the 2-inch diameter barrel of the long focal length component so that large-format light pollution and nebular filters can be employed.

Thanks to the short 1.25 chrome sleeve of 0.94”, all Hyperion’s are principally compatible with spotting scopes, including high-end units by Leica, Swarovski, and Zeiss. For Zeiss Diascope models we already offer an 1.25-inch Diascope-Bayonet Adaptor

See below a chart for the Hyperion eyepieces when using the Baader Fine Tuning Rings. Click here to see the fine tuning rings on our website.


Average Rating (4 Reviews):  
Write a Review and share your opinions!

Simply Superb!
25 July 2015  | 

I have the 10mm & 13mm and I'm extremely impressed with the huge approx 30mm diameter sight glass that the two have, the eye relief is long too which makes these eyepieces a joy to use.

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14 of 14 people found this review helpful.

Fantastic value and very versatile
02 April 2015  | 

I bought a 17mm Hyperion and the tuning rings after watching the video on this page and looking at chart at the bottom. It's my first 'proper' eyepiece from the standard plossl and the Eyeopener Kit. I was a bit skeptical of how it would perform when altering the focal lengths with the rings, but after a good couple of nights with it, my mind was at ease. It's crisp sharp right to the edge of the view and the detail and colours through it are such a joy to look at. The generous field of view and eye relief do seem to retain even when using the fine tuning rings to alter the focal length. This is the only eyepiece I really use now, I'm that impressed with it. I don't use it in the 2" mode as I don't have a 2" diagonal so I can't comment on that part. I'll definetely be buying some more Hyperions to give me a large range of focal lengths. For the price and versatility, you can't beat these for general viewing if you want an upgrade from standard 'budget' eyepieces.

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13 of 13 people found this review helpful.

13 December 2013  | 

If like me you dont have a huge budget then eyepiece selection can be difficult.

i finaly decided on an 8mm & 13mm baader eyepiece.
for the money i would have to say these are the best eyepieces on the market for their price bracket.
serious astronomers that split hairs would find the odd defect but for & average joe theyre absolutely i dont think theres another eyepiece on the market that shares the same functional attributes.

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23 of 23 people found this review helpful.

Baader Hyperion 8mm eyepiece
09 December 2013  | 

I use an 8mm Baader Hyperion as the main eyepiece in my 12” f 4.9 Dobsonian and it is excellent. It gives crisp, edge to edge focus, and the generous field is ideal for the Dob – less nudges per minute!
I also put in a 28mm FTR to make it into a very good 5mm eyepiece for the few nights when the seeing is good enough. In this mode it seems to retain the generous 68 degree apparent field, but there is a noticeable loss of eye relief. You have to fold down the rubber eye-cup; an adjustable screw-out cup would be nice here.
It can be converted to a 22mm focal length by removing the front lens group, but then the eye relief seems to virtually disappear so I’ve never made use of this mode. (I’ve already got a perfectly good 25mm eyepiece.)
Another minor point is that although it can be mounted in a 2” eyepiece holder, my focuser will not extend far enough out to focus it like this. I would need to add a 1” extender tube, so it has always been used in the normal 1.25” holder.

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23 of 24 people found this review helpful.

Some items that are showing as in stock are in stock at our holding warehouses, not at the shop. To double check the stock levels at the shop, please contact us on 01909774369 or

The delivery times for most items is 1 - 2 days but again, please double check stock levels on important orders before placing an order via the website.

The delivery costs for courier next day are for mainland UK only. If you live in the Scottish Highlands/Islands, Channel Islands or Northern Ireland, then a shipping surchage will apply. please contact us for prices. Smaller items can still go 1st class via Royal Mail.

Please note that if you are wanting to take advantage of our Saturday and Sunday timed services or next day pre 12 or pre 10:30 services, you MUST check that the stock is here at the shop before placing orders. Also, orders using the Saturday and Sunday services must be placed before 1pm the previous working day. Also, please remember to check that the stock is here at the shop before placing orders. If the stock is not at the shop, we won't be able to ship on any of the timed services. 

Please note International customers will need to contact us for a shipping price prior to ordering via the website. We don't ship all items internationally. It is at our discretion what we ship outside of the UK. This all depends on the size and weight of the items. Please get in touch with us for any postage costs. Please note we do NOT ship telescopes or heavy items outside of the UK. This is due to massive postage costs and problems regarding returns.

If you have any questions regarding stock levels or delivery, please get in touch.

Zygo Interferometer Testing For ED Refractor Telescopes!

We are extremely pleased to announce our Zygo Interferometer is now installed and ready for use! Our experienced staff can test refractor lenses up to 120mm aperture and provide a comprehensive 2 page report showing the optical quality and Strehl ratio, plus much more information. We are using the very latest Zygo MX software to provide a more detailed report compared to other standard reports.


The interferometer is essentially a measuring instrument. Within the interferometer is a calibrated laser that is pointed through the optical test surface, then onto a high quality reference sphere, then back through the test subject then to an internal camera which gives us the measurement on the screen. From this, we can adjust the position of the test optic and the reference sphere to obtain a perfectly calibrated system. The more central the laser to the test optic and then on return, the better and more accurate reading and measurement we can take. This takes a lot of adjustment to get the best results from the optical surface. Once the measurement has been taken, we are provided with a series of results that show the optical quality of the surface plus other information. Continue reading for an explanation of the individual values and you can also see a test report that was done on one of our RVO Horizon 60 OTAs. 

We are offering certain telescopes with a Zygo test at an extra cost. Mainly ED doublets and triplets. All available telescopes with a Zygo test report are listed here. Just select Zygo Test Report from the drop down box at the top of the listing and we will test the optics in house and provide a full 2 page report with your scope. This will show you the optical quality of your telescope optics. We can also offer this service on your refractor telescope. Please get in touch for more details about this. 

At Rother Valley Optics, one thing we pride ourselves on is customer service and quality of our equipment. When we test your telescope, we will ensure that it is of the highest quality otherwise, we will reject the scope under our strict quality control and test another model for your peace of mind. One of the main values to look at when testing a refractor is the Strehl ratio. The higher this number, the higher quality lens you have. At Rother Valley Optics, we will guarantee the highest possible Strehl ratio for your telescope.  We will aim to provide 0.95 Strehl or higher on Takahashi, RVO Horizon, William Optics and many more! Generally, the higher the Strehl ratio, the lower the Astigmatism and Coma meaning a better image quality from your instrument. 

Other measurements such as the PV and RMS are important too. With these measurements, the lower the number the better as it shows less curvature on the lens. The flatter an optical lens, the better it will perform. The PV rating (Peak To Valley) is a measurement from the highest point (Peak) to the lowest point (Valley). From this we get the RMS (Root, Mean, Square). This is a similar figure to the PV and measured exactly the same way. The RMS is basically an average height difference from the PV so again, the lower the better. As you can see form the example below, we measured an RMS of just 0.027 wave which is a very good value.

We also measure the Power with our systems which is essentially the error from the reference sphere to the test optic. The reference sphere we use on our system is a very high quality sphere so the closer to zero the Power, the less error between the 2 elements thus ensuring a higher quality optical surface. 

You will also see some more values such as Astigmatism and Coma. Again, these are measured by the interferometer when we take measurements of the optical surface after adjustment. These are values which ideally would be at 0 but as our test optics are all curved lenses, there will always be astigmatism and coma present. The lower the number, the less of these aberations you will effectively see but with most refractors, you can buy field flatteners which will compensate for the coma anyway. The astigmatisms value is explaining the error between the symmetrical curvature of the lens. Basically, no lens will be perfectly symmetrical, the lower the astigmatism, the more symmetrical the lens surface is. 

Once the Zygo test report has been completed, the optical alignment is thoroughly tested and tuned to ensure they are spot on before they leave us. 

All available telescopes are on the website at the link below and ones we've tested already that are available straight away are also listed.

Here is an example of the test what we provide. This was a test on one of our Horizon 60 ED OTA's.

For any questions about this amazing new service, please either call 01909774369 or email


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