Taking design inspiration from the venerable Ethos line but with a narrower field of view and longer eye relief, the Tele Vue 72° Delos 3.5mm Eyepiece was designed for long-duration lunar and planetary observation. Its adjustable-height rubber eyecup helps to enhance contrast by preventing stray light from entering the user's peripheral vision which can degrade the image seen through the ocular. Anti-reflective multi-coated optics further ensure sharp, bright, high-contrast, and color faithful images across the entire spacious 72° apparent field of view. The eyepiece is offered with a 1.25" diameter barrel for compatibility with a wide variety of filters and accessories, and is parfocal with Tele Vue Group B eyepieces so no refocusing is required when switching between eyepieces within the group.