Tele Vue 13mm 1.25"/2" 100° field Ethos


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The 100° apparent field of this new TeleVue 13mm Ethos eyepiece provides a field area more than 50% larger than the "space-walking" 82° field of a 13mm Nagler . . .
Our Product #: TE13
TeleVue Product #: ETH-13.0
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Product Description

A review in Sky & Telescope magazine gave the 13mm Ethos five stars, meaning "Sensibly perfect. No meaningful improvements possible." The reviewer commented, "As revolutionary today as the original 13-mm Nagler eyepiece was when it was introduced in 1981, the 13-mm Ethos sets a new standard for wide-field observing. The on-axis performance is second to none, while the 100° apparent field is unprecedented for an astronomical eyepiece . . . if I were dropped on a desert island tomorrow with the 12-inch scope and only one eyepiece, I'd want it to be the Ethos."

With a 13mm focal length that evokes that of the original and revolutionary 13mm Nagler eyepiece, the field of this new 100° apparent field Ethos eyepiece is nearly 50% larger in area than the 82° field of a "space-walking" 13mm Nagler. The TeleVue Ethos delivers the true field size of a longer focal length (but narrower apparent field) eyepiece, but has the benefits of the higher power and darker sky background that are inherent in a shorter focal length.

There is a soft rolldown eyecup to shield the eye from ambient light (from a neighbor's security light, for example) and improve the image contrast. At a usable eye relief of 15mm, the 13mm Ethos would normally somewhat vignette the field of view for eyeglass wearers. However, since the 100° field is so wide that you can't see the full field without having to move your head from side to side to take it all in anyway, vignetting in the conventional sense is not a problem.

The 13mm Ethos has all the virtues that professional and amateur astronomers have come to expect from a TeleVue eyepiece: high contrast, comfortable eye relief, and full field sharpness - with well-controlled astigmatism, field curvature, lateral color, angular magnification distortion correction, and low pupil sensitivity (kidney bean effect) for daytime use. While sharpness is inherent to the optical design itself, the contrast is maximized through the intelligent use of flat finished baffles and ultra low reflectance, high efficiency coatings that are tuned to the glass composition of each lens element.

The Ethos has concentric 1.25" and 2" barrels that allow it to be used in both 1.25" and 2" focusers and star diagonals without the need to change the diagonal or eyepiece adapter. A safety groove is machined into the 2" chrome barrel to engage your focuser thumbscrew. This will help prevent the eyepiece from falling should the thumbscrew accidentally loosen while observing.

The barrel diameter of the current version of the 13mm Ethos has been reduced slightly to 62mm, from the 63.5mm of the first versions to be shipped. This will allow the use of two 13mm Ethos eyepieces in a binoviewer, providing a minimum interpupillary distance of 62mm. This spacing will be usable for the majority of observers, but some people with narrower than average eye spacing may not be able to use this combination. If you are a very serious binoviewer astronomer, a pair of 13mm Ethos may be worth a try.

A commentary on a Cloudy Nights forum, quoted by TeleVue, said, "Forget about the 100-degree field (well . . . I know you can't but . . .), this is quite simply the finest eyepiece I've ever seen - period! Contrast, sharpness, light-throughput, etc. are all just amazing. There is simply NO ghosting or other internal reflections . . . the background is jet-black and the stars (even in my 28" f/3.66) are absolute diamond-points to the very edge!(P> "I've owned and used all of the "gold standards" over the years and NOTHING I've seen can match this!

"Along with about a half-dozen other observers we did "A/B" testing with other top-of-the-line 13 and 14mm eyepieces (M-51, Thor's Helmet and M-42 were the targets). EVERYONE agreed that the ETHOS seemed to add additional inches of aperture. The increased detail in all of the objects was instantly apparent!

"As a bonus, the fine detail on Saturn equaled or exceeded the best "planetary" eyepieces any of us had ever used. And, again, NO ghosting or internal reflections. This baby does it all.

"And, as for the 100 degree field, Vic said it best . . . 'you feel like you're going to fall in' . . . 'the scope just gets out of the way and it's like you're standing in space looking at the objects.'"

The 13mm TeleVue Ethos eyepiece will accept TeleVue Dioptrx eyesight astigmatism correcting lenses.

Tech Details

Barrel Size 1.25"/2"
Eye Relief 15mm
Field of view 100
Focal Length 13mm
Weight 20 oz.
Warranty Limited Lifetime


Review by:
I’m a lens designer (aka lens bender, Code-V jockey, optical design engineer). I’ve been crazy about astronomy and telescopes since I was five. Finally, after many years and many eyepieces, I decided to splurge and get a 13mm Ethos. It’s expensive, but I told my wife that it could be a lot worse. I could collect Corvettes! It is everything all of the other reviewers say it is. The 100-degree FOV is absolutely amazing. It’s exceedingly difficult to design a manufacturable 100-degree eyepiece with tack sharp stars all the way to the edge like this. It’s easy to imagine that you are floating in space. If it isn’t too heavy and the focal length isn’t too short for your scope and seeing conditions, you will love it. (Posted on 11/1/2019)
Review by:
I liked this eyepiece so much that for awhile it, along with a Barlow, would often be the only eyepiece I took out with me for use with my f/6.7 Dob. It was a little heavy for that scope (especially with a Barlow), and I'll never be a fan of TeleVue barrel undercuts, but it was so comfortable to look through, and the 2mm exit pupil with the wide field of this eyepiece was a joy to use. I'd swap in the Barlow for globular clusters. (Posted on 10/17/2019)
Review by:
This is one of my most used eyepieces. Love the wide fields, and the medium focal length frames a lot of objects well in my 12.5” f4.5 Newtonian. (Posted on 8/1/2019)
Review by:
The best eyepiece I've ever used. Totally immersive. Yes, it is heavy and expensive, but 13mm is the sweet spot in many scopes and looking through this thing is like floating in space. (Posted on 1/14/2019)
Review by:
Great views in short and medium length refractors. (Posted on 1/5/2019)
Review by:
Trying the 8mm Ethos early in a past sale made me follow up with the 13mm and 4.7mm. These all weigh less than the 17 and 21, and the 13 is a reasonable weight for balance. I use it in a 2-inch diagonal in two different refactors (with kids growing up the smaller scope and the 8mm are off at college). In the shorter scope the 13mm gives a wide 2.5 degrees at 38x view for DSO in wide, sharp context or easy alt-az tracking. In the longer scope at 70x and 1.5 degrees it's used for closer looks at lunar and planetary views and smaller or denser DSO.

While eyepieces can't remove chromatic aberration, they can avoid adding more false color to what the telescope objective produces. The Ethos show less false color compared with a few other eyepieces of 68 - 82 degree field of view that I tried in the same scopes, this is noticeable on the limb of the moon and as bright objects move off the center of the view. The wide field and high image quality of the Ethos fit well with the approach of using fewer eyepieces to span lowest to highest useful magnifications. (Posted on 1/5/2019)
Review by:
I have a 12.5 " reflector. In my opinion there's not another eyepiece of this focal length that can compete with this eyepiece. It is a co-favorite to use with this scope ( the other being the Nagler 31 mm) . I used to have an 18" and I had the same opinion of it then. (Posted on 12/27/2018)
Review by:
This was the first Ethos that I purchased. I had heard that the view was immersive but I was not ready for the sense of being out in space that this eyepiece provides. My only gripe is that the eye relief is too tight to see anywhere near the field stop while wearing glasses. (Posted on 12/10/2018)
Review by:
I heard a lot about this eyepiece before purchasing it. It is my first and only Televue eyepiece, and I settled on the 13mm Ethos after having used wide-FOV eyepieces (20mm, 9mm, and 3.5mm 100/110-deg) for most of my observing this past summer. The edge-to-edge image consistency is where this eyepiece is truly exceptional to me. I especially like the views of the 13mm Ethos in my 80mm f/7 apo triplet and 102mm f/9.8 achro. I wasn't particularly amazed by the views using my 180mm f/15 mak-cass, but the consistent focus of stars at the edges of this eyepiece is great. While it is a heavy eyepiece, it is significantly lighter than my other 100-deg eyepieces; at 21 oz., the 13mm Ethos is a lightweight compared to the 42 and 33 ounces of my 20mm and 3.5mm William Optics XWAs, respectively. The 13mm Ethos is a fine eyepiece and it is no wonder so many amateur astronomers say such good things about it. (Posted on 11/15/2018)
Review by:
The 13mm Ethos is an absolutely spectacular eyepiece. I use mine primarily in a 18" Obsession Classic f4.5 and rarely switch it out. Combined with a Paracor, images are sharp edge to edge, even on the planets, which is a real luxury on a dob without tracking. The views are pure and expansive. Planetary images are crisp and clear, with subtle shading and tremendous detail on both Jupiter and Saturn. Globular clusters are wonderful. Star colors are obvious. Nebula and galaxy contrast is fabulous. The moon is a whole new experience. It's super easy to use, with none of the kidney-bean blackout or sensitivity to eye position that I've had trouble with on some earlier designs. I use it for outreach as my standard eyepiece and everyone seems to be able to use it easily, even first time viewers, which I think says a lot.

I really can't say enough about this eyepiece. Although it's pricy, for me it's worth every penny and it became my favorite the moment I tried it in my scope. I also have the 6mm and 8mm versions, which are great, but the 13mm is the real standout for my scope and viewing style. (Posted on 8/4/2017)
Review by:
I thought long and hard before spending $650 on an eyepiece, having taken up this hobby 7 months ago. It cost twice what my used Dobsonian telescope did. However, the consensus on the Cloudy Nights forums and others is that the Ethos 13mm is probably one of the finest eyepieces made, hitting the sweet spot as a mid focal length with a wide field of view.

The field is flat and true right to the edge of the incredible 100 degree AFOV. I initially bought it to use in my 1.25" adapter but have since decided that my future eyepieces will all support 2". The Ethos does both. Add to that a lifetime warranty and this becomes an investment that will be with me for decades.

I purchased this over the phone and it was shipped (free) the next day, insured and signed for. Astronomics was great. (Posted on 8/4/2017)
Review by:
If I were asked to limit myself to 2 eyepieces, this would definitely be one of them (the Pentax XW 7mm being the other). As an eyeglass wearer, the 15mm eye relief it at the edge of what I like, but the wide angle views are absolutely stunning. The contrast is very good, and you get near edge to edge sharpness. The eyepiece is extremely well made, and more than likely you're going to keep this eyepiece no matter what scope you use. (Posted on 8/4/2017)
Review by:
This is one of my favorite and most heavily used eyepieces (next to the 17mm Ethos). I use this in an 8 SE (with and without a focal reducer), and I really love the wide field of view. Everything you have read about the Ethos line where it is described as "like floating in space", I have found to be true. I have to move my head around to get the full field of view, but I don't mind that. The contrast and eye relief are great as well, but the really wide view is what I love the most.

The 13mm is a little heavy (around 1.3 pounds, according to Tele Vue) but the weight is not at all detrimental. I have it in a William Optics 2" diagonal on my 8 SE with the standard mount and the views are solid. The motor does not struggle a bit and the balance is fine. One other thing is that I have 2" filters, so when I ordered this eyepiece, I also ordered Tele Vue's 2" barrel extender (manufacturer part number EBX-2120) so that I can use my 2" filters with it.

The Ethos eyepieces are pretty expensive but they are worth it to me. I am buying eyepieces in order to (hopefully) keep them around for life, so I view it as a good investment for any telescope that I will get in the future as well. This eyepiece is a joy to use and I am very happy to own it. (Posted on 8/4/2017)
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