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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 Nebula Filter CLS - 1.25"
Explore Scientific Nebula Filter CLS - 1.25"

Explore Scientific Nebula Filter CLS - 1.25"

by Explore Scientific
SKU ES-310225
$109.99 - $119.99
$109.99
$109.99 - $119.99
$109.99
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  • City Light Suppression (CLS) Filter
  • Enhances Contrast for Deep-Sky Objects
  • Available in 1.25" and 2" Sizes
  • Ideal for Viewing Nebulae and Galaxies
  • Threads Directly into Standard Eyepieces
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Explore Scientific Nebula Filter CLS - 1.25" & 2"

    The Explore Scientific Nebula Filter CLS, available in standard 1.25" and 2" formats, is a general-purpose light pollution filter engineered to darken the sky background and significantly increase contrast on a wide range of deep-sky objects.

    Broadband Contrast Enhancement for Urban Skies

    This City Light Suppression (CLS) filter works by selectively blocking common wavelengths of artificial lighting, such as sodium and mercury vapor streetlights, which are the primary cause of urban skyglow. By rejecting this unwanted light while transmitting the key wavelengths emitted by deep-sky objects, the filter provides a dramatically darker sky background. This isolates faint nebulae and galaxies from the washed-out backdrop, making them easier to detect and observe.

    A General-Purpose Filter for Nebulae and Galaxies

    Unlike narrowband filters that target specific emission lines, the CLS is a broadband filter designed for versatility. It improves the view of all types of deep-sky objects, including emission nebulae like the Orion Nebula (M42), reflection nebulae, and even broadband targets like the Andromeda Galaxy (M31). This makes the Explore Scientific CLS an excellent first filter for an observer looking for a single, effective tool to combat light pollution across the celestial catalog.

  • How does the Explore Scientific CLS filter improve views from a suburban backyard?

    The Explore Scientific CLS filter darkens the sky background by blocking the most common wavelengths of light pollution from streetlights. This increases the contrast between your target object and the sky, making faint details in nebulae and galaxies more visible, even from moderately light-polluted areas.

    What is the difference between the Explore Scientific CLS and a UHC filter?

    A CLS (City Light Suppression) filter is a broadband filter, meaning it passes a wider range of light, making it effective on galaxies and star clusters in addition to nebulae. A UHC (Ultra High Contrast) filter is a narrowband filter that passes a much smaller range of light, primarily the OIII and H-beta lines from emission nebulae. A UHC provides higher contrast on those specific targets but is less effective for broadband sources like galaxies.

    Can I use the Explore Scientific CLS filter for astrophotography?

    Yes, the CLS filter is a popular choice for beginner to intermediate astrophotographers using color cameras (DSLR, Mirrorless, or One-Shot-Color astro cameras). It helps capture better data from light-polluted locations by reducing skyglow, leading to improved contrast and color balance in the final image.

    Will the Explore Scientific CLS filter help me see the Orion Nebula (M42) with my 8" Dobsonian?

    Absolutely. The Orion Nebula (M42) is a bright emission nebula that responds extremely well to a CLS filter. With an 8" telescope, the filter will darken the surrounding sky significantly, making the faint, extended wings of the nebula pop into view and revealing more structure within the bright core.

    How will the Explore Scientific CLS filter affect views of the Andromeda Galaxy (M31)?

    The Andromeda Galaxy (M31) is a broadband target, meaning it emits light across the entire visible spectrum. The Explore Scientific CLS filter will help by dimming the skyglow around the galaxy, which can make its faint outer arms easier to trace. While it will slightly dim the galaxy itself, the contrast enhancement often results in a more detailed overall view, especially of the dust lanes near the core.

    Does the Explore Scientific CLS filter thread into all standard 1.25" and 2" eyepieces?

    Yes. Both the 1.25" and 2" versions of the Explore Scientific CLS filter feature standard filter threads. They are designed to screw directly into the barrel of any corresponding 1.25" or 2" eyepiece or accessory, such as a filter wheel or camera nosepiece.

  • GTIN 812257017195
    Available Sizes 1.25", 2"
  • Explore Scientific Warranty