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IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
IMPORTANT: Our store is located in Canada. All orders that include products manufactured outside of Canada or USA will be subject to tariffs and duties, regardless of the order value. US customers are responsible for all applicable duties and tariffs, and those will be billed by the carrier, except for the Lacerta upgrade kit, for which we collect them at checkout.
Explore Scientific 92° 17mm Long Eye Relief Waterproof Eyepiece - 2"
Explore Scientific 92° 17mm Long Eye Relief Waterproof Eyepiece - 2"

Explore Scientific 92° 17mm Long Eye Relief Waterproof Eyepiece - 2"

by Explore Scientific
SKU ES-EPWP9217-01
$369.99 - $369.99
$369.99
$369.99 - $369.99
$369.99
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  • 17mm Focal Length
  • 92° Apparent Field of View
  • 2" Barrel Diameter
  • Long Eye Relief Design
  • Argon-Purged Waterproof Construction
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  • Explore Scientific 92° 17mm Long Eye Relief Waterproof Eyepiece - 2"

    The Explore Scientific 92° 17mm eyepiece delivers a hyper-wide 92° apparent field of view in a rugged, waterproof 2" barrel. Its 17mm focal length provides the medium-high magnification needed to resolve detail in globular clusters and galaxies, while the vast field makes finding and tracking your targets effortless.

    A 92° Window on the Universe at 17mm

    With an apparent field of view of 92°, this eyepiece creates a true "spacewalk" experience, dissolving the boundary between you and the night sky. The 17mm focal length is ideal for resolving individual stars in globular clusters like the Hercules Cluster (M13) or revealing the faint structure in galaxies like the Whirlpool Galaxy (M51).

    This combination of magnification and field width frames celestial objects in a way that narrower designs cannot, providing context and an immersive sense of scale. The generous long eye relief design further enhances comfort during long observing sessions, reducing eye strain as you take in the expansive view.

    Argon-Purged for a Lifetime of Dew-Free Views

    Unlike standard eyepieces, the Explore Scientific 92° 17mm is hermetically sealed and purged with inert argon gas. This process makes the eyepiece completely waterproof, preventing internal fogging when moving from a warm environment to cold outdoor temperatures—a common issue that can end an observing session.

    This sealed construction also protects the delicate internal multi-coatings from dust, fungus, and moisture for the life of the eyepiece. You get consistent, high-contrast views every time you observe, without worrying about internal contamination or dew.

    How 92° Benefits Non-Driven Scopes

    The vast 92° field of view is a significant advantage for users of non-driven telescopes like Dobsonians. An object will remain in the field of view for a remarkably long time before your telescope needs to be nudged, allowing for more relaxed, uninterrupted study of faint details.

    This wide expanse of sky also aids in the use of averted vision. When hunting for faint objects like the Veil Nebula (NGC 6960), the extra space around your target makes it easier to look slightly to the side, placing the image on a more light-sensitive part of your retina and revealing details that are invisible to direct vision.

    ES 92° 17mm vs. Tele Vue Nagler 17mm: Field and Durability

    The Tele Vue Nagler series is a benchmark for sharp-to-the-edge performance. The Explore Scientific 92° 17mm, however, offers two distinct advantages for the field observer.

    • Wider Apparent Field: The 92° apparent field of the Explore Scientific is significantly more immersive than the 82° field of the 17mm Nagler Type 4, creating a more dramatic viewing experience.
    • Waterproof Construction: The argon-purged, sealed design of the ES 92° eyepiece provides a level of environmental protection against internal dew and contaminants that is not a standard feature of the Nagler line.

    For observers prioritizing the widest possible view and all-weather durability, the Explore Scientific 92° 17mm presents a compelling choice.

  • What is the main advantage of the Explore Scientific 92° 17mm eyepiece's field of view?

    The primary advantage of the 92° apparent field of view is the incredibly immersive, "spacewalk" experience it provides. For users of non-driven telescopes like Dobsonians, it also means objects stay in the field of view much longer, requiring less frequent manual adjustments.

    Why is an argon-purged eyepiece like the ES 92° 17mm better for field use?

    An argon-purged and sealed eyepiece is completely waterproof. This prevents internal optics from fogging up when you take it from a warm house into the cold night air. It also permanently seals out dust, moisture, and fungus, protecting the lens coatings and ensuring high-contrast views for years.

    How will the ES 92° 17mm perform on globular clusters like M13 in an 8" f/6 Dobsonian?

    In an 8" f/6 Dobsonian (1219mm focal length), the 17mm eyepiece yields about 72x magnification. This is an excellent power for viewing the Hercules Cluster (M13), providing enough magnification to resolve its dense core into individual stars while the 92° field frames the cluster beautifully against a dark sky background.

    Is the 17mm focal length of this ES 92° eyepiece a good choice for the Orion Nebula (M42) in a 10" f/10 SCT?

    In a 10" f/10 SCT (2540mm focal length), this eyepiece provides 149x magnification. This is a relatively high-power view that will not fit the entire Orion Nebula (M42) in the field. However, it is an exceptional choice for examining fine details within the nebula's core, easily resolving the four main stars of the Trapezium (Theta Orionis) and the intricate cloud structures surrounding them.

    Is the Explore Scientific 92° 17mm eyepiece suitable for eyeglass wearers?

    Yes, this eyepiece is designed with long eye relief for enhanced viewing comfort. This generally allows observers who wear glasses for astigmatism to see most or all of the 92° field of view without having to remove their glasses.

    How does the Explore Scientific 92° 17mm compare to an 82° eyepiece at the same focal length?

    The ES 92° 17mm provides a noticeably larger and more immersive apparent field than an 82° eyepiece. This creates a more compelling visual experience and allows celestial objects to drift through the field more slowly, which is a significant benefit for observers with manual telescopes.

  • Focal Length 17mm
    Apparent Field of View 92°
    Barrel Size 2"
    GTIN 812257017379

    • Explore Scientific 92° 17mm Eyepiece

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  • No manual or software is available for this product.

  • Explore Scientific Warranty