Tele Vue 17mm 2" Nagler Type 4


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The TeleVue 2" 17mm Nagler Type 4 is a premium-quality eyepiece that further refines the "spacewalk" observing experience of the original Nagler and Nagler Type 2 eyepieces that have been the optical standard of the industry for years . . .
Our Product #: TN17
TeleVue Product #: EN4-17.0
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Product Description

The TeleVue 2" 17mm Nagler Type 4 is a premium-quality eyepiece that further refines the "spacewalk" observing experience of the original Nagler and Nagler Type 2 eyepieces that have been the optical standard of the industry for years.

The 17mm Nagler has increased eye relief, higher contrast, and reduced pincushion compared to the original Naglers. This makes it exceptional for achieving a wide field of view at medium power with Dobsonian scopes.

The 17mm has TeleVue's unique "Instadjust" click-stop adjustable-height eyeguard, with a soft fold-down rubber eyecup. With the eyeguard retracted all the way, all of its generous eye relief is available for eyeglass use. The eyeguard can be raised in small and repeatable increments to position the eye of the non-eyeglass wearer the precise distance from the eyepiece to see the full field of view with maximum suppression of ambient stray light. A special doughnut-shaped removable plastic insert fits into the eyeguard to center the eye for those who have trouble positioning their eye precisely on a small exit pupil.

The 17mm is primarily designed for no-holds-barred medium power deep space use with scopes having focal ratios down to f/4. It is marvelous for open clusters, nebulas, and globular clusters with any scope, but is particularly effective with fast f/ratio reflectors. That being said, it must also be noted that its very wide field also makes it convenient for moderate power lunar and planetary observing with Dobsonians, as you have much longer to observe before the planet drifts out of the field and the scope has to be repositioned.

Please note the weight of this eyepiece if you have a Dobsonian telescope. Its use may require some temporary rebalancing of your scope, or the use of a TeleVue #TVEQC equalizing adapter with 1.25" eyepieces to avoid balance problems.

Tech Details

Barrel Size 2"
Eye Relief 17mm
Field of view 82
Focal Length 17mm
Number of optical elements 6
Weight 26 oz
Warranty Limited Lifetime


Review by:
This is probably my favorite and most used eyepiece. Offers excellent field correction at f/5 with no perceptible edge of field brightening. Great eye relief, even for eye-glass wearers. I use this unit frequently for galaxy hunting and observation, as it provides a higher magnification and darker background than longer focal length eyepieces. (Posted on 10/28/2019)
Review by:
A must have in any eyepiece lineup. Great mid-range eyepiece that offers a wide field of view with a comfortable viewing experience. Still like the Pentax Xl for crisp focus but each eyepiece is complimentary to the strengths of the other. Imho, if you can only have a few eyepieces in your bag this is one of the ones that needs to be there. (The Pentax should be there too!) (Posted on 10/17/2019)
Review by:
Great immersion, not Ethos good, but the field stop is easier to see. Biggest complaint, though not huge by any means, is eye placement can be a bit tricky. I find my Hyperions and XWs to be much easier to use, BUT, with less wow factor. (Posted on 1/8/2019)
Review by:
Not too long, not too short. But just right! This eyepiece is the one I use the most to give me wide enough field of view with enough magnification to bring out the best my optics can offer. (Posted on 10/30/2018)
Review by:
This and the 12mm T4 are my longest tenured and still most used eyepieces in my kit. Comfortable to use with great contrast and very sharp. Highly recommended. (Posted on 10/8/2018)
Review by:
I use this eyepiece with an 8" f/6 newtonian and it's one of my top three favorites. It has generous eye relief for eyeglass wearers like me. Over the years, I've gravitated toward long eye relief eyepieces for ease of viewing. While it's quite a chunk in the hand, it's heft about matches my other T4 Naglers so re-balancing when switching eyepieces is not an issue. I tried some Ethos eyepieces a while back, but overall I didn't enjoy using them as much as this one. I'd buy this eyepiece again in a heartbeat. (Posted on 10/6/2018)
Review by:
It's spectacular wide field is especially good for locating small planetary nebula like M57 . Used with a narrow band nebula filter, the sky glow disappears revealing emission areas in high contrast. I've never imagined views of deep sky objects were possible in such a small scope. Sweeping through the Sagittarius star fields is amazing! I highly recommend this eyepiece. (Posted on 10/6/2018)
Review by:
I have been using telescopes for years. My first was a Dobson 8" and I had 3 eyepieces and a barlow that were "no name". Later, I bought a name brand set and was surprised that I didn't see much difference. I got into imaging a couple of years ago and spent a lot on new refractors, a C11 and cooled cameras. I still used my old eyepieces but rarely. This summer, I decided to buy a premium eyepiece - the 17mm Nagler Type 4 to look at the great display of planets. All I can say is wow! The contrast and clarity blew me away. I viewed the planets with my C11 with this eyepiece and then used a Televue Barlow for more magnification. I realized I needed another premium eyepiece so I got an 11mm Nagler to go with it. They may be pricey but the improvement in visual observing is well worth it. (Posted on 10/6/2018)
Review by:
I have one and love it. Televue quality is unbeatable. It works well with both my 8” Edge HD and my 80mm refractor. (Posted on 10/6/2018)
Review by:
I love my 17mm nagler. It provides beautiful views at 71 mag, and yields 1.1 degree true field. The sky seems very, very dark with bright pinpoint stars to the edge. Very easy to focus and find the sweet spot. The build is rock solid and I'm sure it will last many generations. Definitely not the cheapest but they put out a great product. My eyes can't find any fault in them. CW (Posted on 8/4/2017)
Review by:
The wide field is spectacular and seems sharp and impressive, my first look at Orion's sword with 6-inch f/5 floored me. I guess that's the "immersion" described for this eyepiece.

If you like the Radian instadjust feature (I do) you may find that 17 T4 takes a little getting used to: somehow, it's not just a bigger Radian for learning eye placement. View is great once you get it adjusted and get used to the larger diameter of the 17 T4.

Views thru short tube achromat and smaller f/5 reflector are stunning, a real treat for viewing larger-scale DSO. A paracorr cleans up coma in the reflector, the field is so wide you notice it in wide ring of outer field otherwise.

The size and 1.5 pound weight of this 17mm T4 (and the 27 Pan for another example) seem to be upper end of moderate weight that not's as bad for balance or feeling like a diagonal is overloaded, compared to the largest 40+mm 68 degree, 30+mm 82 degree or 20+mm 100 degree eyepices, some of which are 2-3 pounds.

I got the 17 T4 and 19 Pan at different deep sales about the same time, thinking they would be similar I would pick one to keep. Turns out I really like both, with 17 T4 a deep sky/dark sky favorite for the extra field of view in shorter focal length scopes, and the 19 preferred for moon, planets and deep sky details in f/10 scope. (Posted on 8/4/2017)
Review by:
Good, but not perfect. It suffers from field curvature requiring refocusing of the edges. It as has a tiny amount of astigmatism at the edge. These are both minor nits, but the center just does not snap into focus compared to the Pentax XL or XW lines or the Delos line. You are never quite sure if you have achieved best focus. It's almost as if there is astigmatism in the center. Off center seems slightly sharper. The immersion factor is great, no complaints at all there. 17mm of eye relief seems overstated. At that distance, you can see about 70 degrees at most. To get the true field stop, you must press in and then the exit pupil becomes difficult to hold. It's easier to just tilt your head to take in the edge. The eyeguard stayed put once set. Barlows quite well. A bit heavy at over 1 1/2 pounds. Very dense feeling in the hand. Recommended only if you must wear glasses and need an 82 degree field at this focal length. I would give it 9 out of 10 stars, but with only 5 stars max instead of 10, I'll give it the benefit of the doubt with 5 stars. (Posted on 8/4/2017)
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