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Explore Scientific 120° 9mm Waterproof Eyepiece -2"
Explore Scientific 120° 9mm Waterproof Eyepiece -2"

Explore Scientific 120° 9mm Waterproof Eyepiece -2"

by Explore Scientific
SKU ES-EPWP12009-01
$899.99 USD - $899.99 USD
$899.99 USD
$899.99 USD - $899.99 USD
$899.99 USD
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  • 9mm Focal Length
  • 120° Apparent Field of View
  • 2" Diameter Barrel
  • 12 Elements in 8 Groups
  • Argon-Purged Waterproof Construction
  • Tapered 2" Barrel
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  • Description
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  • Explore Scientific 120° 9mm Waterproof Eyepiece - 2"

    The Explore Scientific 120° 9mm Waterproof Eyepiece pairs a 120° apparent field, Explore Scientific's widest, with a 9mm focal length. It has 12 elements in 8 groups, a tapered 2" barrel and an O-ring sealed, argon-purged waterproof housing.

    The 120° Apparent Field at 9mm

    The 9mm 120° is in a class by itself, with an apparent field unlike anything you have experienced before, and this widest field will submerge you in night sky views.

    While many hyper-wide eyepieces offer low magnification, the 9mm focal length provides a close-up, high-power view of your target. You see even more of the sky and also see the main attraction, whether a nebula, a galaxy or a star cluster, close up: the best of both worlds.

    Optical Design: 12 Elements in 8 Groups

    The eyepiece uses 12 lens elements in 8 groups. Explore Scientific does not publish more about its glass or coatings.

    • Averted Vision Enhancement: Hyper-wide eyepieces make it easy to gaze slightly to the side of an object, which puts the image on a part of your eye that is more sensitive to light, allowing you to see fainter images.
    • Optimized for Non-Driven Scopes: Objects stay in the field a long time, especially noticeable without a drive, as with a Dobsonian or a refractor on a grab and go mount like the Explore Scientific Twilight I.

    Argon-Purged Waterproofing

    The 120° is built on the same waterproof eyepiece concept: O-ring sealed and purged with an inert gas to create a waterproof environment.

    The eyepiece needs a 2-inch focuser. Like the rest of the waterproof series, it has a tapered 2" barrel for extra security.

  • What magnification does the 9mm give?

    Divide the telescope focal length by 9: about 67x at 600mm, 133x at 1200mm and 222x at 2000mm.

    What does "Argon-Purged" mean for the Explore Scientific 120° eyepiece?

    Each eyepiece is O-ring sealed and purged with an inert gas to create a waterproof environment, with a fog-proof housing.

    What are the best targets for the Explore Scientific 120° 9mm eyepiece?

    Good targets are nebulae, galaxies and star clusters, seen close up with plenty of surrounding sky.

    How will an Explore Scientific Focal Extender affect the view with this 9mm eyepiece?

    A focal extender increases the magnification of any eyepiece with the same barrel size. The 2" FE02-020 2x gives this eyepiece the magnification of a 4.5mm.

    Why is a 2-inch barrel necessary for the Explore Scientific 120° 9mm eyepiece?

    A 120° field at 9mm needs a field stop of roughly 9 × 120 / 57.3 ≈ 19mm, and the large optics behind it, so Explore Scientific builds it with a 2" barrel.

    How is the 120° field of this eyepiece different from a 100° eyepiece?

    At the same magnification a 120° field is 20% wider than a 100° field. 120° is the widest apparent field Explore Scientific makes.

    How should I clean the waterproof Explore Scientific 120° 9mm eyepiece?

    Because the eyepiece is sealed, only the outer lens surfaces need cleaning, and only when needed.

    Which telescopes suit the 120° 9mm?

    Any telescope with a 2" focuser. The long time objects stay in view is especially noticeable without a drive, as with a Dobsonian or a refractor on the Explore Scientific Twilight I.

  • Focal Length 9mm
    Apparent Field of View 120°
    Barrel Size 2"
    Construction Argon-Purged, Waterproof
    GTIN 812257013876
    Elements / groups 12 in 8 groups
    Eye Relief 12.5 mm

    • Explore Scientific 120° 9mm Waterproof Eyepiece -2"

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  • Explore Scientific Warranty