Explore Scientific 100° Series 2" 25mm Waterproof Eyepiece

The 100° Series 25mm is a flagship-class ultra-wide-field eyepiece delivering breathtaking panoramic views through a 2" barrel at low magnification. At 100° with a 25mm focal length, the true field of view is enormous — large star-forming regions, galaxy clusters, and sweeping Milky Way panoramas fill the eyepiece with an immersive sense of depth that no narrower design can replicate.

The premium multi-element optical design uses high-quality glass types to maintain sharp, well-corrected images across the entire hyper-wide field. Even in fast telescopes (f/5 and faster), the 100° series delivers strong edge performance. Argon-purged waterproof construction ensures the optics stay sealed and fog-free through the worst dew and humidity conditions.

At $899, this sits in premium eyepiece territory — but it directly competes with Tele Vue Ethos eyepieces that cost comparably or more, while adding waterproof construction that the Ethos line lacks.

Key Features

• 100° apparent field of view — hyper-wide panoramic framing for the most immersive deep-sky views possible through a 2" barrel
• Premium multi-element optics — high-quality glass types deliver sharp, color-corrected images with strong edge correction across the enormous field
• 2" barrel for maximum light throughput at the long focal length
• Argon-purged waterproof housing — sealed against moisture, fog, and temperature extremes, a feature that most ultra-wide-field competitors lack
• Enhanced Multi-Layer Deposition (EMD) coatings on all air-to-glass surfaces with edge-blackened elements for maximum contrast
• Fold-down silicone rubber eyecup with comfortable eye relief for extended viewing sessions

Ideal For

• Wide-field deep-sky observers who want the most immersive views possible — large nebula complexes, Milky Way star clouds, and galaxy groups at their most expansive within a 100° panoramic field
• Dobsonian and large-aperture telescope owners seeking the ultimate low-power, hyper-wide-field eyepiece for sweeping deep-sky observing
• Observers comparing to Tele Vue Ethos — the 100° series delivers comparable field width and optical quality with the added benefit of waterproof construction
• Star party showcase — the 100° field creates genuine "wow" reactions from both experienced observers and first-time visitors