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 |
Reviews
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)
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)
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)
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)
