About this product
Part Number: ENZ-0306
This is the "ultimate" tool for tweaking out the last bit of power that the atmosphere will permit.
Concept / Background: I did not set out to design a zoom eyepiece, per se. David and I were discussing characteristics we'd like in a superior "planetary" eyepiece, and the zoom feature answered one of the major goals; how to obtain the highest possible useful magnification on a given night considering the ever-changing atmosphere. There were other aspects of equal importance and only the combination of all would satisfy our ethos in creating a "planetary" eyepiece: full field sharpness for any speed telescope, high contrast and transmission for natural color rendition, low scatter, and comfortable eye-relief. Being a zoom, we also concerned ourselves with making sure it was parfocal through the zoom range as well maintaining a constant apparent field of view. The one aspect we were not too concerned with was giving the eyepiece a wide AFOV.
Limiting the AFOV to 50° and the eye-relief to 10mm, we were able to create a compact physical design employing only five elements to reach the optical goals. Like other "Naglers," it utilized a negative lens group ahead of the focal plane. This permitted relatively long eye-relief for very short focal lengths. By independently moving the upper and lower lens groups, we achieved constant focus (parfocality), constant apparent field of view, and essentially constant eye-relief. Just by rotating the upper barrel, you can zoom through the power range. Click stops offer known power points for reference without needing to look at the barrel and instantaneously choose the optimum magnification for the given observing conditions.
I was sufficiently confident in the design and purposely decided to attach my name to the zoom, despite the common association between "Nagler" and 82° AFOV. I felt it was more important to stake our reputation on overcoming the "degrading zoom reputation" than maintaining the 82° assumption for "Nagler" designs.
— Al Nagler
- 50º constant apparent field of view
- Click stops every mm
- 3-6mm Zoom
- Proprietary tuned full multi-coatings & high index glass
- Blackened lens edges & Anti-reflective threads
- Fold-down, rubber eyeguards & grip rings
- Threaded for 1.25" filters
- Safety undercut in nosepiece barrel for extra locking security
- 100% full field visual inspection on Tele Vue's own flat-field test instrument guarantees the performance of every Tele Vue eyepiece
- Supplied with eyeguard and nosepiece cover
Eyepiece Field of View Simulator
|Model ||3-6mm |
|Focal Length (mm) ||3-6 |
|Barrel Size (in.) ||1¼" |
|Apparent Field of View (deg.) ||50 |
|Eye Relief (mm) ||10 |
|Weight (lb / oz) ||0.33 / 5.3 |
|Field Stop (mm) ||5.1 - 2.6 |
|Average Rating (3 Reviews): |Excellent eyepiece and service
Friday, 19 November 2021 | Barry
With so many things becoming as rare as hen's teeth, it was a delight to obtain this, the last in stock at the time - and well worth it. Primarily for use in my CFF 105 f/6 for fast set up for when a brief window of viewing opportunity opens up, and for travel. Excellent choice - and very fast service even to outside a major town on the other side of the world.
Very nice, quality eyepiece
Tuesday, 6 April 2021 | Nicola
I bought this eyepiece primarily for my Takahashi FC76-DCU, due to its light weight and portability for travel, as well as the excellent reviews online. It is clearly a top quality eyepiece, very solidly made yet not too heavy. I have only had a chance to test it on M42 and Sigma Orionis so far, but the views were crystal clear and I look forward to using it for planetary and moon viewing. Overall, highly recommended.
Friday, 17 May 2019 | David
A crystal clear little eyepiece! I was doing some close examination of the lunar surface and it's ideal to search for an area then zoom onto it. Very well made with excellent glass. Especially handy if travelling light!!
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