Tele Vue 3mm to 6mm Nagler 1.25" zoom eyepiece


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Unlike an ordinary zoom eyepiece, this high power Nagler zoom maintains a constant and substantial 50 degree apparent field of view at all focal lengths and the usable eye relief stays a constant 10mm . . .
Our Product #: TNZ
TeleVue Product #: ENZ-0306
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Product Description

In conventional zooms, the apparent field of view and the usable eye relief change as the focal length changes. Likewise, objects go markedly out of focus as the magnification is changed, as conventional zooms are not parfocal (they don't focus at the same point at all focal lengths). These anomalies don't happen with the Nagler zoom. The Nagler zoom physically lengthens and contracts as the focal length is changed, as can be seen in the feature images you can click on above.

This unique approach (all other zooms move lenses within their body to change their focal length) allows the apparent field, eye relief, and focus to stay the same, no matter what the focal length. You don't have to constantly adjust the focus as you change powers, as you do with other zooms (minor tweaking may be necessary, however). And you don't have to adjust your eye position to accommodate a changing eye relief and a changing field stop diameter.

The Nagler zoom has five fully-multicoated elements in three groups, similar to a fine camera lens. By keeping the number of optical elements low, the contrast stays high when compared with other zooms that have an additional two or three light-scattering lenses in their light path. The eyepiece has click stops at 3mm, 4mm, 5mm, and 6mm for quick changes to precise preset magnifications. Naturally, you can use any intermediate focal length between the click-stops, as well. There's a fold-down rubber eyeguard and a rubber grip ring.

The Nagler zoom is designed to provide the best balance of contrast, comfortable eye relief, and resolution for the critical planetary observer, particularly those with ultra-premium short focal length refractors. It allows the observer to dial in the right balance between magnification, exit pupil, and atmospheric turbulence to achieve the best possible image for the observing conditions at any given moment.

If you own an ultra-premium short focal length refractor, or any other top quality scope, there's no longer a reason to have to accept second best when it comes to high power lunar and planetary observing. There's finally a zoom eyepiece that matches the quality of your scope optics. This Nagler zoom will put to rest forever the idea that it is impossible to produce a zoom eyepiece that does not degrade the image.

Tech Details

Barrel Size 1.25"
Eye Relief 10mm
Field of view 50
Focal Length 3mm-6mm
Number of optical elements 5
Weight 5 oz
Warranty Limited Lifetime


Review by:
One of my favorite eyepieces, perfect for planets and deep sky alike. I find the eye relief to be perfect as I don't observe with my glasses. Views are sharp and contrasty. Is it as good as a regular focal length eyepiece? A resounding yes on all but the absolute best nights and even then, the difference is minuscule. Highly recommended. (Posted on 10/1/2019)
Review by:
Love or hate it, the versatility of the Nagler Zoom cannot be overstated. Covering focal lengths between 3-6mm, this can replace as many as 4 fixed focal length eyepieces. Coupled with its optical quality, it is a terrific value for the money. It provides sharp Nagler-quality views and is virtually parfocal across its range of focal lengths. It has 10mm eye relief across the range, which is very good for such short focal lengths. Many find this to be too tight, though, so a couple of Delos or DeLites may be a more usable option. In my 80mm f/6 refractor this covers magnifications from 80-160x and produces exit pupils from 0.5-1mm, which is the perfect range for this scope. It has click stops at 3, 4, 5 and 6mm, but can be fine-tuned anywhere in between to suit the observing conditions.

The tradeoff for the excellent Zoom optics is the reduced apparent field of view - 50 degrees. Honestly, this is just as much field as you get in a good Plossl, and the Zoom retains that full field across the range, so unless you really have to have a massive field of view at high power, you’re not really missing much. Plus, you’ll probably get better eye relief from the Nagler Zoom than a comparable focal length Plossl.

If you can use it comfortably, it’s hard to find a better high power eyepiece than the Nagler Zoom. (Posted on 1/8/2019)
Review by:
My favorite eyepiece for planetary viewing. Travels with me in my TV-76 case everwhere I go. I love that its parafocal. Works great in all my APOs! (Posted on 12/31/2018)
Review by:
This is my favorite planetary eyepiece. I wear glasses and the eye relief is tight, but the optics are so good that I am ok with the tight eye relief. I love that it is parafocal. When planetary viewing, this is such a useful and necessary feature. I can quickly find the optimal zoom and demonstrating the effects of magnification vs contrast to others is very easy. This eyepiece will not get in the way of your view! (Posted on 12/31/2018)
Review by:
Agreed that the eye relief is not that great for eyeglass users, but the rubber around the eye lens really helps. Compares well to single focal length eyepieces and is a perfect companion for those short focus refractors when you need planetary magnifications. (Posted on 11/22/2018)
Review by:
I have this eyepiece for planetary work. I like the fact you can dial in the magnification to anything between 3mm and 6mm. There are positive stops every 1mm, however you can easily set it to (for example) 3.3mm or 5.7mm. Eye relief is very acceptable - even with glasses. I plan to pair this up with a TV 2x barlow and see how well that does in my NP101is. (Posted on 11/6/2018)
Review by:
This is my first Tele Vue eyepiece. I have a 4" f/5 rich field telescope, but like to have an occasional look at the planets and moon. I didn't want to invest in several high power eyepieces that I wouldn't use that much. I had seen very good reviews on this eyepiece and the fact that your getting really 4 eyepieces in one, I just couldn't pass on getting it. The views are better than I expected. Very sharp and crisp images with great contrast even at the 3mm setting, and the eye relief stays constant throughout the entire zoom range. (Posted on 10/31/2018)
Review by:
Use this for any astro viewing. Excellent performance on planetaries. A small bit of light loss but still sharp with nice contrast. The variable magnification is a huge plus for me. The power can be adjusted according to sky conditions if needed. I find the eye relief to be acceptable but tight. (Posted on 10/24/2018)
Review by:
This handy zoom will quickly become your go-to eyepiece for planetary viewing. At high magnifications it eliminates the risk of losing the object outside of a new field of view when switching out eyepieces. Change of magnification is done by easily dialing the edge of the eyepiece in and out and stopping where the seeing is best, saving a lot of time too. (Posted on 10/10/2018)
Review by:
A lightweight compact zoom great for evenings where I want high power but seeing is variable as it often is here under the jet stream. Can comfortably interchange it with lightweight planetary eyepieces when using an alt az mount. Saw white ovals on Jupiter using this zoom this year with a 140mm f 7.7 refractor (Posted on 10/10/2018)
Review by:
Products by Tele Vue are excellent this EP is not the exception. I own very few zooms EP’s because they loose performance somewhere. This one is a great performer in all focal lengths. A pleasure and easy to adjust while viewing. Also parfocal with other TV EP’s which makes it a working system. (Posted on 10/6/2018)
Review by:
This EP isn't the most used in my kit, but on a very good night it does the job so well that my other two short focal length EPs often stay in the drawer. The very best view that I ever had of Saturn was with this TV zoom. (Posted on 10/6/2018)
Review by:
The Nagler Zoom lets you quickly adjust magnification as atmospheric conditions change. Doesn't compromise on sharpness or contrast. Pairs well with short fast refractors. I find that eye relief is just barely acceptable with eyeglasses. (Posted on 10/6/2018)
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