Al Nagler

Eyepieces TeleVue eyepieces. Row 1: 20 mm, 26 mm, 32 mm, 40 mm Plössls. Row 2: 19 mm, 24 mm, 35 mm Panoptics. 5 mm Nagler T6, 7 mm Nagler T1, 7 mm Nagler T6, 9 mm Nagler T1, 13 mm Nagler T6, Nagler 3-6 mm Planetary Zoom. Row 3: 13 mm, 6 mm, 8 mm, 21 mm Ethos. By 1979, Nagler designed his first eyepiece, a wide-field telescope eyepiece termed the "Nagler". Compared to other eyepieces, the view through a Nagler eyepiece is more expansive and appears to wrap more around your vision. As an observer, Nagler enjoyed low magnification "rich field" viewing of extended "deep sky" objects such as galaxies, star clusters, and nebulae, and the Nagler eyepiece was meant to produce such experiences. eyepieces, Nagler released the first ultrawide Nagler eyepiece, the 13 mm Nagler, in 1980. The introduction of the 13 mm Nagler eyepiece is considered a benchmark in amateur astronomy. It was the first eyepiece to provide an 82° wide field with sharp images all the way out to the edge of view. The eyepiece also coincided with the introduction of the Dobsonian reflecting telescope. Nagler eyepieces are well-designed for observing such large, dim, and extended objects.

Highlights of the Nagler line are the 20mm Type 2 released in 1986 and the 31 mm Type 5 released in 1999. The 20 mm (now discontinued) featured a 2" barrel and weighed 2.3 lbs. In Tele Vue ads, a miniature Nagler was shown leaning against the side of the 20mm Nagler. The 31 mm Nagler, featuring a 2" barrel and weighing 2.2 lbs, is referred to as the "Terminagler" eyepiece.

TeleVue would introduce other eyepiece lines such as the Radian and Panoptic. developed a 100° apparent field eyepiece. David named the new eyepiece line Ethos, and the first product was a 13 mm eyepiece, the 13 mm Ethos, which was meant to acknowledge and draw comparison to the original 13 mm Nagler. TeleVue introduced two additional eyepiece series that were influenced by work on the Ethos line, the 72° Delos and 62° DeLite.

Nagler wrote an article that was published in the July 2006 issue of Sky & Telescope Magazine. "How to Choose Your Telescope Magnification" was viewed as helpful in guiding consumer purchases of specific telescope and eyepiece combinations. In particular, Nagler claimed that refracting telescopes had no lower limit of magnification unlike telescopes with a central obstruction such as catadioptrics (Schmidt-Cassegrain) and Newtonian reflectors.

Telescopes Nagler first built a telescope, an 8" Newtonian reflector, in 1955 while a high school student in the Bronx. The MPT spawned the production and evolution of TeleVue's flagship 4" apochromatic telescope line, which would experience various name changes and eventually culminate in the "Nagler-Petzval" (NP) series. All of these telescopes would offer two-inch focusers and diagonals and be based on the four-lens Petzval design providing color-free viewing with the ability to change from low power, wide field observing to high magnification views of the moon and planets. Later offerings such as the TeleVue-60 and TeleVue-85 employ a doublet (two lens) apochromatic objective lens assembly.

In May 2002, TeleVue became the North American distributor of Vixen Optics telescopes and astronomical equipment. Vixen is a Japanese optics company that was started in 1949. Vixen had established a name by providing well-made German equatorial telescope mounts along with various telescopes and eyepieces. Distribution of Vixen Optics telescopes and equipment was later taken over by Company Seven of Montpelier, Maryland.

Retirement and legacy

Nagler retired in 2005 and his son David assumed the presidency of TeleVue. Nagler spent his retirement traveling to star parties and meeting other amateur astronomers. In 2009, Nagler met astronaut Alan Bean at the Stellafane Telescope Maker's Convention where he was a keynote speaker. Bean had trained in Nagler's simulator during the Apollo moon landing program.

In March 2025, just a few weeks before Nagler's 90th birthday, the PUNCH (Polarimeter to Unify the Corona and Heliosphere) constellation of satellites was launched. The four satellites feature a TeleVue designed objective lens in each Wide Field Imager camera. The satellites were developed to study features of the solar corona. This was the first time that TeleVue optics have been sent into space. In 2009, a TeleVue NP101 refracting telescope had been used as an observing instrument in Antarctica with the ASTEP (Antarctic Search for Transiting ExoPlanets) initiative to discover exoplanets from a south pole location.

In an interview published in the Summer 1995 issue of Amateur Astronomy, Nagler stated that his work on eyepieces and telescopes had two major goals: “to make astronomy as easy and versatile as possible to encourage, rather than discourage, newcomers, and secondly, to provide a visual experience as close to a “spacewalk” as possible by obtaining the widest, sharpest, highest contrast views."

Nagler died at the office of Televue in Chester, New York, on October 27, 2025, at the age of 90.

Asteroid 10715 was discovered by astronomer Brian Skiff in 1983 at Lowell Observatory. Skiff named the asteroid for Al Nagler, and its official designation is 10715 Nagler.