A Wide-Field Window for High-Power Observing
The Delos 6mm provides a 72-degree apparent field of view that feels expansive at high power. This moderately wide field makes it easier to locate and track objects, especially with non-driven mounts, as the target drifts more slowly across your view. The optical system is engineered to maintain sharp, high-contrast star points and planetary details across the entire field, largely free of distracting lateral color or edge-of-field astigmatism, even in fast f/ratio telescopes.
For the observer, this means you can study the delicate banding on Jupiter or the Cassini Division in Saturn's rings without the planet softening as it moves away from the center. The wider field provides a more immersive context, framing the target against a dark, velvety background, which makes the experience more like looking through a porthole than a keyhole.
Maximum Contrast Through Advanced Coatings
Every air-to-glass surface in the Delos 6mm receives Tele Vue's proprietary index-matched multi-coatings, while the lens edges are meticulously blackened. This two-part approach is critical for high-magnification work, where maximizing light throughput and minimizing scatter are paramount. The coatings ensure that the maximum amount of light from the target reaches your eye, while the blackened edges prevent stray light from bouncing between elements and reducing contrast.
The visual result is a view with a starkly black background, allowing faint planetary details, subtle lunar crater floor textures, and the dim companions of double stars to stand out. This high signal-to-noise ratio is what separates a good view from a memorable one, especially when pushing the limits of your telescope on a night of steady seeing.
Consistent 20mm Eye Relief for Viewing Comfort
One of the defining features of the Delos series is its consistent, long 20mm eye relief. Unlike many high-power eyepieces that force you to press your eye against the lens, the Delos 6mm allows you to maintain a comfortable distance. This is a significant advantage for eyeglass wearers, who can see the entire 72° field of view without removing their glasses. For all observers, it reduces eye strain during long sessions, allowing your eye to relax and perceive more subtle details.
Precision Tuning with the Locking Eyeguard
To complement the long eye relief, the Delos features an adjustable, locking eyeguard. This mechanical system allows you to set the perfect distance between your eye and the top lens, effectively tuning the eyepiece to your unique facial structure and preference, with or without glasses. Once you find the sweet spot where the full field is visible without blackouts or "kidney-beaning," you can lock it in place for repeatable, instant comfort every time you use it.
Observing with the Delos 6mm
On a night of good seeing, insert the 6mm Delos into a quality 4-inch refractor to achieve around 160x. Center on the lunar crater Clavius. The view is not just a flat white disk; the high-contrast optics reveal the subtle grayscale variations in the crater floor and the crisp shadows cast by the central peaks. The 72° field allows you to take in the entire crater and its surroundings without feeling cramped, and the long eye relief lets you study the details for minutes on end without fatigue.
The main limitation of any high-power eyepiece is its dependence on atmospheric conditions. The 6mm focal length will deliver very high magnification in most telescopes, and if the seeing is poor, the image will appear soft or blurry. On such nights, a lower-power eyepiece will provide a more satisfying view. However, when the atmosphere is stable, the Delos 6mm provides a level of detail that makes waiting for those nights worthwhile.
Is the Delos 6mm a good choice for my 8" Dobsonian?
Yes, it's an excellent choice. In a typical f/6 Dobsonian, a 6mm eyepiece yields 200x magnification, a sweet spot for planetary and lunar detail. The 72° field of view provides more time to observe an object as it drifts, which is a major advantage with a non-tracking mount.
How does the Delos 6mm compare to the Nagler 5mm?
The Delos prioritizes viewing comfort with 20mm of eye relief, making it ideal for eyeglass wearers. The Nagler provides a wider 82° field but has a tighter 12mm eye relief. If you value comfort and wear glasses, choose the Delos; if you want the most immersive field possible and don't require long eye relief, the Nagler is a strong option.
Can I use the Delos 6mm with a Barlow lens?
You can, but it will result in extremely high magnification that is only usable on nights of exceptional atmospheric stability. A 2x Barlow would yield magnifications often too high for most telescopes and seeing conditions. The Delos is designed to be a primary high-power eyepiece on its own.
What is the main benefit of the locking eyeguard?
The locking eyeguard allows you to set the perfect eye distance to see the full field of view without blackouts. Once you find your ideal position, you can lock it, so it's perfectly set for you every time, saving adjustment time in the dark.
Do I need DIOPTRX if I have astigmatism?
If you have astigmatism, you can observe with your glasses on thanks to the Delos's long eye relief. However, using the DIOPTRX allows you to observe without glasses, removing extra layers of glass for a higher-contrast view and providing a perfectly sharp focus customized for your eyes.
