Tele Vue Delos 12mm 72° Eyepiece - 1.25"

The 72° Apparent Field Optical System

The Delos optical design achieves a wide 72° apparent field of view while maintaining exceptional control over aberrations. Every glass surface is fully multi-coated, and lens edges are blackened to maximize light throughput and suppress internal reflections. The result is a bright, high-contrast image with a neutral color balance, allowing the natural hues of planets and stars to be observed without artificial tint.

This level of correction makes the 12mm Delos a versatile performer. On a short focal length refractor, it can frame open clusters like the Pleiades with pinpoint stars across the field. In a large Dobsonian, it provides the magnification needed to resolve fine detail in globular clusters such as M13, where the wide field helps to frame the object against a dark, velvety background.

Consistent 20mm Eye Relief and Adjustable Eyeguard

A defining feature of the Delos line is its comfortable and consistent 20mm of eye relief across all focal lengths. This is a significant benefit for observers who wear eyeglasses for astigmatism, as it allows you to see the entire 72° field without having to press your glasses against the lens. You can simply leave your glasses on and enjoy the full view.

To accommodate observers who do not wear glasses, Tele Vue developed an intuitive sliding, locking eyeguard. This mechanism allows you to set the height of the soft rubber eyeguard to the perfect position for your eye, effectively blocking stray light and preventing blackouts. Once set, it stays put, ensuring a comfortable and repeatable viewing position every time you use the eyepiece.

Ready for Dioptrx Astigmatism Correction

For observers with astigmatism who prefer not to wear glasses at the eyepiece, the Delos series is fully compatible with the Tele Vue Dioptrx system. The eyeguard housing is specifically designed to accept any Dioptrx corrector, which simply drops into the top of the eyepiece. This allows you to dial in your precise astigmatism correction, ensuring the sharpest possible views without corrective lenses in the way.

A Flat Field for Sharpness Edge-to-Edge

The Delos optical formula is engineered to produce a flat focal plane, a critical performance factor, especially in well-corrected telescopes. This means that if a star is in sharp focus in the center of the field, it remains a tight point of light all the way to the field stop. This characteristic is vital for lunar and planetary observing, where you want to see uniform sharpness across the entire disk of Jupiter or the Moon's terminator.

The trade-off for this level of correction in a compact 1.25" barrel is weight. The Delos 12mm is a substantial eyepiece, and its mass is a direct consequence of the large, high-index glass elements required to achieve this performance. While it balances well on most telescopes, it is a point of consideration for users with very small, lightweight instruments.

Maximizing Contrast with Internal Baffling

Beyond the lens coatings, the internal mechanics of the Delos are optimized for contrast. All interior surfaces are treated with anti-reflective finishes, and sharp-edged baffles are placed to intercept stray light paths. This attention to detail pays off when observing faint details near bright objects, like trying to spot the Cassini Division in Saturn's rings or resolving faint craterlets on the floor of Plato on the Moon.

Secure Fit with the 1.25" Barrel and Safety Undercut

The Delos 12mm uses a standard 1.25" barrel for broad compatibility with any telescope accepting this format. It features a machined safety undercut, which is a groove that allows the focuser's set screw to securely lock the eyepiece in place. This provides peace of mind, helping to prevent the eyepiece from accidentally slipping out of the focuser if a screw loosens slightly during a cold night.

Observing with the Delos 12mm

Imagine using the 12mm Delos in an 8-inch, f/10 Schmidt-Cassegrain, yielding about 169x magnification. Centered on Jupiter, the planet's disk is large and sharply defined. As your eye adapts, the main equatorial belts resolve into finer, parallel bands with subtle coloration. The Great Red Spot, when visible, stands out not just as a smudge but as an entity with structure, all while the Galilean moons hang like sharp diamonds in the dark space nearby, perfectly in focus even at the edge of the view.

Choosing Your Mid-Power Tele Vue Eyepiece

The Delos 12mm occupies a space between several other Tele Vue families, each with distinct advantages.

• vs. Nagler 12mm Type 4: The Nagler offers a wider 82° apparent field, creating a more pronounced "spacewalk" effect. However, the Delos provides significantly more eye relief (20mm vs. 12mm), making it the clear choice for observers who wear eyeglasses. The Delos is also often perceived as having slightly higher contrast for planetary viewing.
• vs. Panoptic 15mm: The 15mm Panoptic has a smaller 68° apparent field and is much lighter than the Delos. It is an excellent choice for a lower-power, grab-and-go eyepiece. You would choose the 12mm Delos when you need more magnification and prefer its longer eye relief and slightly wider, more corrected field.