Explore Scientific 100° 30mm Waterproof Eyepiece - 3"

The 100° Panoramic Experience in a 30mm Eyepiece

With a 100° apparent field, the boundary of the eyepiece seems to dissolve, leaving you with an unrestricted, inky-black vista. This immense field makes it easier to locate targets and is a significant advantage for users of non-driven telescopes, such as large Dobsonians. Objects drift through the field of view for an extended time before your telescope needs repositioning.

This wide-field presentation also makes it easier to use averted vision. By looking slightly to the side of a faint galaxy or nebula, you place the image on a more light-sensitive part of your retina. The relaxed, panoramic view of the 30mm 100° eyepiece makes this technique feel natural, helping you perceive subtle details in faint deep-sky objects.

A 3" Barrel for Unrestricted Low-Power Views

To achieve a true 100° field of view at a 30mm focal length, a standard 2-inch barrel is not large enough to accommodate the necessary optics without introducing significant vignetting. The Explore Scientific 100° 30mm eyepiece solves this by moving to a 3-inch barrel, allowing for larger lens elements and an optical design that is fully illuminated to the edge of the field.

This design choice is critical for providing the lowest-power, widest possible true field of view in large telescopes. The result is maximum light throughput and a panoramic view that simply cannot be replicated in a smaller barrel format at this focal length. All optical elements are fully multi-coated and edge-blackened to ensure the highest possible contrast.

Argon-Purged: Waterproof to 1 Meter

Each eyepiece in the 100° series is built to withstand harsh observing conditions. The optical housing is internally sealed and purged with inert argon gas, which prevents the formation of internal fogging during nights with heavy dew or rapid temperature changes. This process also protects the delicate internal coatings from moisture, maximizing their lifespan.

To guarantee this seal, every eyepiece is factory-tested by being submerged in 1 meter of water for 30 minutes. This rugged construction ensures your investment is protected from the elements, delivering consistent, high-contrast views every time you observe.

ES 30mm 100° vs. 2-Inch Wide-Field Eyepieces

While legendary 2-inch eyepieces provide expansive views, the 3-inch format of the ES 30mm 100° pushes the physical limits of what's possible for low-power viewing.

• vs. TeleVue 31mm Nagler: The 31mm Nagler is a benchmark for wide-field viewing in a 2-inch barrel, offering a superb 82° field. The ES 30mm 100°, by utilizing a 3-inch barrel, expands the apparent field to a full 100°, creating a more immersive, "spacewalk" sensation at a nearly identical focal length.
• Trade-offs: The primary advantage of the 3-inch format is the wider, unvignetted field at long focal lengths. The trade-off is the requirement for a 3-inch focuser and the eyepiece's considerable size and weight, which may require counterbalancing on some telescopes.