TeleVue Ethos-SX 3.7mm 110° Eyepiece - 1.25"/2"

The Ultimate High-Resolution Tool

At 3.7mm, you are accessing the top tier of your telescope's resolving power. The 110° field removes the "tunnel vision" usually felt at these magnifications, replacing it with an immersive vista that keeps you oriented within the star field.

• Lunar Prowess: Perfect for high-power exploration of rilles, dome structures, and the central peaks of craters like Tycho or Aristarchus.
• Double Star Specialist: The extreme magnification and 110° field make it easier to split tight doubles while still seeing the surrounding star field for context.
• Compact Deep Sky: Ideal for magnifying small planetary nebulae or the cores of globular clusters, where the tiny 0.3mm to 0.5mm exit pupil (depending on your scope) provides an inky black sky background.

This eyepiece excels in short focal length refractors and fast Newtonians, where it provides high resolution without the magnification becoming unusable due to atmospheric turbulence.

Atmospheric Limits and Performance

The 3.7mm Ethos SX is a performance-first optic. Because it generates such high magnification, its performance is closely tied to the quality of your night sky. On nights of average seeing, the view may appear "soft" due to the atmosphere; however, on steady nights, this eyepiece will reveal details you simply cannot see with longer focal lengths.

For observers with large, fast Dobsonians, the 3.7mm SX often becomes the go-to choice for pushing the limits of the mirror's resolution. It provides the "drift time" necessary to observe comfortably without the constant, frantic nudging required by narrower 50° or 60° planetary eyepieces.

Hybrid Mounting and Professional Build

The 3.7mm SX features the Tele Vue hybrid 2" / 1.25" barrel, ensuring it fits into almost any high-quality focuser or diagonal. To maintain the highest possible contrast at these power levels, Tele Vue utilizes advanced multi-coatings and internal baffling to eliminate stray light and ghosting.

In fast Newtonian systems (f/4.5 or faster), using a Tele Vue Paracorr Type 2 is highly recommended. This ensures that the stars remain pinpoint sharp across the entire 110° field, allowing you to utilize every millimeter of that massive field stop for high-resolution observation.