Assessing TeleVue's Optical Line-up: Insights on Ethos, Nagler, Delos, and Further Models
Tele-Vue's Portfolio of Advanced Telescope Eyepieces
Tele-Vue, a renowned manufacturer of high-quality telescope accessories, has a diverse lineup of six eyepiece series—Ethos, Nagler, Delos, Panoptic, DeLite, and Plossl. Each series is designed for specific observing needs, varying in field of view, comfort, optical performance, and price.
Founding and Innovation
Tele-Vue's journey began with Al Nagler, who leveraged his experience working on lunar landing simulators for the Apollo program to design some of the first high-quality Plossl eyepieces in the 1970s. This was followed by the eyepiece design that bears his name. The Nagler eyepiece design revolutionized then-new fast Dobsonian reflecting telescopes, and Tele-Vue has been leading innovation in telescope eyepiece design ever since.
Tele-Vue's Eyepiece Lineups
Tele-Vue's extensive array of eyepieces includes the following series:
- Tele-Vue Ethos: Introduced in 2007, Ethos eyepieces boast more than eight lens elements to achieve a super-sharp, well-corrected apparent field of view of up to 110°. The shorter focal length Ethos eyepieces provide a handy wide field of view in telescopes without tracking, such as Dobsonians, keeping the target in view longer. These eyepieces also offer a highly immersive viewing experience when observing the Moon and some large, bright deep-sky objects.The Ethos eyepieces have performed well in telescopes as fast as f/2.6, with little in the way of aberrations besides some moderate field curvature at the longer focal lengths. All units offer a decent amount of eye relief.Ethos eyepiece focal lengths and their respective performances include:a. 21mm and 17mm (2" only) - ideal low-power eyepieces in fast focal ratio telescopes.b. 13mm, 10mm, 8mm, and 6mm (hybrid 1.25" or 2" eyepieces) - the 8mm and 6mm require an extension tube or barrel extension to focus in 2" format.c. 3.7mm and 4.7mm - feature detachable 2" to 1.25" adapters.
- Tele-Vue Nagler: Nagler eyepieces, Tele-Vue's flagship product, were the first to be designed. All Nagler eyepieces feature an 82-degree apparent field of view with little distortion, field curvature, or other aberrations. They are a little easier to look through than the Ethos line and are more affordable. Naglers can be used with any telescope, even the fastest ones with a focal ratio of f/2.6 (with a coma corrector).Nagler eyepiece types, focal lengths, and their respective performances include:a. The original Nagler Type 1 eyepieces – big and heavy, with poor eye relief and less-than-great correction in fast telescopes. However, older, secondhand Nagler Type 1 eyepieces can still provide good value for the price.b. Nagler Type 2 – added a massive 2" 20mm unit and some improvements to eye placement and eye relief.c. Nagler Type 3 – never manufactured.d. Nagler Type 4 – improved sharpness and field flatness while adding sliding eyecups to the old Type 2 design. They are still available.e. Nagler Type 5 and Type 6 – much more lightweight and compact, featuring massive improvements in eye relief, especially at the shorter focal length range.
- Tele-Vue Delos: The Delos eyepieces share the same optical design as Ethos eyepieces, with narrower lenses and a narrower true field of view. This makes them cheaper while offering extremely long eye relief. With an apparent field of view of 72 degrees, the Delos design delivers almost perfect views with almost no aberrations at any focal ratio and in any telescope type. Delos eyepieces may be ideal for those who need to wear eyeglasses at the eyepiece due to astigmatism.
- Tele-Vue Panoptic: The Panoptic eyepieces are slightly sharper versions of the Erfle or "SWA" design used in many inexpensive "wide-angle" eyepieces. The Panoptics have an apparent field of view of 68 degrees and work best in telescopes with focal ratios of f/4.5 or slower. The 24mm and 19mm units are suitable for achieving a wide field of view in binoviewers or any 1.25" eyepiece-only small telescopes.
- Tele-Vue DeLite & Radian: The DeLite eyepieces are essentially a further simplification of the Delos line with a narrower 62-degree apparent field but with similarly long eye relief. DeLite eyepieces are an improvement on the old Radian eyepieces, which had a 58-degree apparent field of view but otherwise similar features and performance. The DeLite design is a little sharper and has less scatter than the Delos, Ethos, and Nagler eyepieces, as well as weighing and costing less. However, the apparent field of view is quite narrow.
- Tele-Vue Plossl: Tele-Vue's Plossl eyepieces, their original product, have not changed significantly since their inception. All except the 55mm have a 1.25" barrel diameter, and all but the 40mm offer a 50-degree apparent field of view. They are made to tighter tolerances than most cheaper Plossl eyepieces.
Tele-Vue's wide selection of eyepieces caters to a variety of observing needs, from deep-sky viewing to planetary observation, offering a balance of field of view, comfort, optical performance, and cost. Each series reflects Tele-Vue’s commitment to optical quality, ergonomic design, and a legacy of innovation.
- In the realm of astrophotography, the super-sharp and well-corrected apparent field of view of up to 110° offered by Tele-Vue's Ethos eyepieces makes them ideal for capturing expansive images of celestial bodies.
- The랑леr eyepieces, marked by an 82-degree apparent field of view and minimal distortion, field curvature, or other aberrations, are suitable for various gadgets, including both refractor and reflector telescopes used for observing the moon and planets.
- For those that enjoy planetary observation, the narrow true field of view and extremely long eye relief provided by the Delos eyepieces make them a great choice, especially when utilizing technology like eyeglasses to correct astigmatism.
- With an apparent field of view of 68 degrees, the Panoptic eyepieces serve well in telescopes with focal ratios of f/4.5 or slower, offering a wider field of view when engaged in deep-sky viewing.
- Despite the narrow 62-degree apparent field, the DeLite eyepieces stand out with their improved sharpness and less scatter compared to other Tele-Vue eyepiece series, making them a cost-effective choice for both refractor and reflector telescopes in the field of view technology.
- The original product of Tele-Vue, the Plossl eyepieces, maintain their place in the market, offering a 50-degree apparent field of view suitable for a range of telescopes and basic observing needs.
