Optolong H-Alpha 12nm CCD Filter - 31mm Unmounted - HAL12-31U is no longer available.

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Item #OLNG-HAL12-31U

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  • This Optolong H-Alpha 12nm Narrowband Filter blocks harmful light pollution wavelengths
  • Wavelengths responsible for natural light pollution, or skyglow, will be dramatically reduced
  • Blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter
  • Recommended for cameras with an integrated guiding sensor
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  • Description

    Optolong H-Alpha CCD 12nm Filter - 31mm Unmounted

    This Hydrogen-Alpha 12nm Narrowband Filter is designed by Optolong and is 31mm in diameter. The filter enables a 12nm bandwidth of light, centered on the 656nm wavelength, to pass through. This H-alpha filter blocks light pollution wavelengths which will greatly improve contrast. Wavelengths responsible for natural light pollution, or skyglow, will be dramatically reduced, as is artificial light pollution caused by high and low-pressure sodium vapor and mercury vapor lights. The result is high-contrast images, revealing the H-alpha line in all its glory. Use this filter alone to bring out the H-alpha line in emission nebulae, or use together with OIII and SII filters to get false color emission line images like the Hubble Space Telescope does.

    A 12nm Ha filter is recommended for cameras equipped with an integrated guiding sensor. You’ll have lots more guide stars to choose from with a 12nm filter as opposed to the extra-narrowband 6.5nm version. Like all Optolong filters that are designated as “CCD”, this H-Alpha filter also blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.

    The Optolong 31mm Unmounted 12nm H-Alpha Filter is made with Schott glass that has been multi-coated with an ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength or CWL. This filter is designed for use in color filter wheels that accept 31mm unmounted filters in a round format.

    Please Note: This h-alpha filter is NOT for use on the Sun. To do so could cause irreparable eye damage or blindness. Don’t even think about it!


    Quality Filter Materials:

    • Schott B260 substrate material from Germany, 3.0mm thick
    • Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition


    Optolong Filter Manufacturing Processes and Parameters

    • Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
    • Surface quality, according to MIL-O-13830, is 60/40
    • 90% transmission at H-alpha 656nm
    • Infrared wavelength of 700-1100nm is cut off
    • 0.1% transmission Hg at 435nm and 578nm
    • 0.1% transmission Na at 589nm
    • High-value transmission of pass-band and optical density of off-band is assured through Optolong’s planetary rotation system, a homogeneous and precise coating procedure
    • Each filter comes with a plastic case with high-pressure EVA case lining


    About Optolong

    Optolong is the Astronomy Filters division of Yulong Optics, an optical filter design, and processing company out of Kunming, China that has provided filters for over 700 optical companies since 1999. All Optolong filters pass European Union RoHS requirements and have been certified by TUV Rheinland and Bureau Veritas.


    Supplier SKU


    What's Included

    • Optolong 31mm Unmounted H-Alpha 12nm Filter

    • Filter Case

  • Dimensions & Specifications

    • Filter Size: 31 mm

    • Filter Type: Narrowband Imaging

    • Filter Shape: Round

    • Mounted or Unmounted: Unmounted

  • Product Guarantee

    We stand behind all the products we sell, and your satisfaction is our top priority. If you're not satisfied with the quality of your purchase, simply send the item back to us in its original packaging within 30 days of its delivery.

    Manufacturer Warranty

    Two Years

    Return & Exchange Policy

    At our site, returns are easy! You may return new, unused, and resalable items for a refund or exchange. Simply ensure that the item is returned in its original product packaging within 30 days of delivery.

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