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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.
Explore Scientific Neutral Density Filter ND 0.9 - 2" - Discontinued
Explore Scientific Neutral Density Filter ND 0.9 - 2" - Discontinued

Explore Scientific Neutral Density Filter ND 0.9 - 2" - Discontinued

by Explore Scientific
SKU ES-310240
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$59.99 - $59.99
$59.99
$59.99 - $59.99
$59.99
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  • ND 0.9 Optical Density
  • 12.5% Light Transmission
  • 2-inch Barrel Size
  • Neutral Color Transmission
  • Reduces Glare on Lunar Surfaces
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Explore Scientific Neutral Density Filter ND 0.9 - 2"

    The Explore Scientific ND 0.9 Neutral Density Filter is a 2-inch accessory designed to reduce overwhelming brightness by transmitting only 12.5% of incoming light. This fixed 0.9 optical density provides a comfortable, high-contrast lunar view in telescopes 4 inches and larger, eliminating glare without altering the natural color of your target.

    ND 0.9 Filter: 12.5% Transmission for High-Contrast Views

    This filter provides a fixed optical density of 0.9, which reduces incoming light to a comfortable 12.5% of its original intensity. Unlike variable polarizers, this single-element filter guarantees perfectly uniform transmission across the visual spectrum, ensuring the view is dimmed without introducing any color shift or polarization artifacts. The 2-inch barrel threads directly onto standard 2" eyepieces and accessories, making it an essential tool for managing brightness in medium to large aperture telescopes.

    Lunar & Double Star Observing: Taming Glare Without Color Shift

    For lunar observation in telescopes 4 inches and larger, the Moon's brightness can be so intense that it causes glare and washes out fine detail. The ND 0.9 filter dims the view to a comfortable level, dramatically increasing contrast and revealing subtle features like rilles, crater walls, and maria that are otherwise lost. It is also an invaluable tool for splitting challenging double stars with a large magnitude difference, such as Sirius (Alpha Canis Majoris); by reducing the primary star's overpowering glare, the filter allows the faint companion to be resolved.

  • What does ND 0.9 mean for the Explore Scientific Neutral Density Filter?

    An optical density of 0.9 means the filter transmits only 12.5% of the light that passes through it. This is equivalent to a 3-stop reduction in brightness, making it ideal for viewing extremely bright objects like the Moon.

    When should I use the Explore Scientific ND 0.9 filter instead of a variable polarizing filter?

    Choose the fixed ND 0.9 filter when true color neutrality is critical. While a variable polarizer offers adjustable brightness, it can introduce a slight color cast and polarization artifacts. The Explore Scientific ND 0.9 provides uniform light reduction across the entire visual spectrum for the most natural view possible.

    Is the Explore Scientific ND 0.9 filter too dim for observing Jupiter with an 8" SCT?

    Yes, for most observers, this filter is too strong for planetary viewing. Reducing the light to 12.5% is excellent for the Moon's intense glare but will likely make details in Jupiter's cloud bands too dim to see clearly. A lighter filter, such as an ND 0.3 (50% transmission), is a better choice for planets.

    Why use a 2-inch ND 0.9 filter?

    The 2-inch barrel format allows the filter to be threaded directly onto 2-inch eyepieces and accessories. This is essential for observers using larger telescopes and wide-field 2-inch eyepieces, as it allows them to reduce brightness without causing vignetting or restricting the field of view.

    How does the Explore Scientific ND 0.9 filter help split a double star like Sirius (Alpha Canis Majoris)?

    The primary star, Sirius A, is so bright that its glare completely overwhelms its faint companion, Sirius B (the 'Pup'). The ND 0.9 filter dims the entire system by 87.5%, which reduces the overpowering glare from Sirius A enough for the faint pinpoint of Sirius B to become visible right beside it.

    Will this Explore Scientific ND 0.9 filter change the color of the Moon?

    No. This is a 'neutral' density filter, meaning it is engineered to reduce brightness uniformly across the entire visible spectrum. The Moon will appear significantly dimmer but will retain its natural grey, white, and tan colors without any added color cast.

  • Filter Type Neutral Density (ND)
    Optical Density 0.9
    Light Transmission 12.5%
    Barrel Size 2"
    GTIN 812257017256

    • Explore Scientific Neutral Density Filter ND 0.9 - 2"

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  • Explore Scientific Warranty