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Optolong Variable Polarizing Filter

Optolong Variable Polarizing Filter

by Optolong
SKU OPT-12501
CA$52.00 - CA$64.00
CA$52.00
CA$52.00 - CA$64.00
CA$52.00
Price Match Policy!
  • Continuously Variable Light Transmission
  • Available in 1.25" and 2" Barrel Sizes
  • Ideal for Lunar, Planetary, and Terrestrial Viewing
  • Reduces Glare and Enhances Contrast
  • Durable CNC-Machined Metal Cell
2 in stock
Qualifies for FREE Shipping in Canada on orders over $500.
  • Description
  • FAQ
  • Specifications
  • Warranty

  • Optolong Variable Polarizing Filter

    Available in both 1.25" and 2" barrel sizes, the Optolong Variable Polarizing Filter allows you to continuously adjust image brightness, providing precise glare control on the Moon and bright planets by simply rotating the filter housing.

    Fine-Tune Brightness on the Moon, Venus, and More

    Unlike a standard, fixed-transmission Moon filter, a variable polarizer acts like a dimmer switch for your eyepiece. By rotating the top half of the two-piece filter, you can dial in the perfect amount of light attenuation for any target. This allows you to apply maximum filtering to reduce the overwhelming glare of a full Moon, then back it off to preserve detail on a delicate crescent Moon or when observing Venus.

    Beyond Astronomy: Cutting Glare in Terrestrial Viewing

    This filter's utility extends to daytime terrestrial observation and photography. Just like a polarizing filter on a DSLR camera, the Optolong Variable Polarizer enhances views by cutting through reflected glare. When observing over water or through atmospheric haze, a simple turn of the filter can dramatically increase contrast and make distant details pop.

    Schott Glass Construction in a CNC-Machined Cell

    Optolong builds this filter with high-quality Schott glass, which is then multi-coated using an ion-assisted deposition process. This technique ensures the coatings are durable, scratch-resistant, and optically stable. The filter cell is CNC-machined from lightweight, strong metal, then sand-blasted and black-anodized for maximum durability and stray light control. The result is a slim, robust filter that won't vignette and is built to last.

    Variable Polarizer vs. Fixed Moon Filter: The Key Difference

    A standard Moon filter is a single piece of neutral density glass with a fixed transmission percentage. It works, but it's a one-size-fits-all solution. A variable polarizing filter offers critical flexibility.

    • Fixed Moon Filter: Provides one level of brightness reduction. May be too dark for a crescent Moon or not dark enough for a full Moon at high power.
    • Optolong Variable Polarizer: Lets you set the brightness precisely for the target, your telescope's aperture, and the current seeing conditions, ensuring you never over- or under-dim the view.

  • How do I adjust the brightness with the Optolong Variable Polarizing Filter?

    Simply thread the filter onto a 1.25" or 2" eyepiece or accessory. Then, while looking through the eyepiece, slowly rotate the top ring of the filter. You will see the image brightness change, allowing you to set the most comfortable and detailed view.

    What's the main advantage of the Optolong Variable Polarizing Filter over a standard Moon filter?

    The key advantage is flexibility. A standard Moon filter has a fixed light reduction (e.g., 25% or 13% transmission). The Optolong Variable Polarizing Filter allows you to continuously adjust the brightness, making it adaptable to any lunar phase, planet, or even daytime terrestrial viewing.

    Can I use the Optolong Variable Polarizing Filter for observing the Sun?

    Absolutely not. The Optolong Variable Polarizing Filter is NOT a solar filter and is not designed for direct solar observation. Attempting to view the Sun with this filter will cause immediate and permanent eye damage and will destroy your equipment. Only use certified solar filters for solar viewing.

    Will the Optolong Variable Polarizing Filter improve views of the Moon through my 8" SCT?

    Yes, it's an excellent tool for an 8" SCT. The large aperture of your telescope gathers a great deal of light, making the Moon uncomfortably bright. The Optolong Variable Polarizing Filter allows you to reduce the glare to a comfortable level, which increases contrast and makes it easier to see fine details like rilles, crater walls, and maria.

    How does the Optolong Variable Polarizing Filter work for daytime, terrestrial viewing?

    For terrestrial use, the Optolong Variable Polarizing Filter cuts down on polarized, reflected light. This is especially effective for reducing glare from water, glass, or wet surfaces. By rotating the filter, you can darken the sky, enhance the color of foliage, and see through reflections, improving overall image contrast.

    I'm trying to photograph a waterfall with my telescope; will the Optolong Variable Polarizing Filter help?

    Yes. When used for terrestrial photography, the Optolong Variable Polarizing Filter will reduce the harsh glare off the water's surface and wet rocks. This will allow your camera to capture more saturated colors and detail that would otherwise be washed out by reflections.

  • Available Sizes 1.25" Round Mounted, 2" Round Mounted
    Glass Material Schott Glass
    Coatings Multi-coated with ion-assisted deposition
    Cell Material CNC Machined, Anodized Metal
  • Optolong 3-Year Warranty