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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 Nebula Filter H-Alpha 2-inch 12nm
Explore Scientific Nebula Filter H-Alpha 2-inch 12nm
Explore Scientific Nebula Filter H-Alpha 2-inch 12nm
Explore Scientific Nebula Filter H-Alpha 2-inch 12nm

Explore Scientific Nebula Filter H-Alpha 2-inch 12nm

by Explore Scientific
SKU ES-310130
$249.99 - $249.99
$249.99
$249.99 - $249.99
$249.99
Price Match Policy!
  • Isolates the Hydrogen-alpha emission line at a 12nm bandpass
  • Standard 2-inch filter format for modern focusers and filter wheels
  • Dramatically increases nebula contrast under light-polluted skies
  • Engineered for deep-sky astrophotography
  • Includes an individual test report to guarantee performance
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Nebula Filter H-Alpha 2-inch 12nm

    The Explore Scientific Nebula Filter isolates the critical Hydrogen-alpha emission line with a 12nm bandpass, specifically designed for 2-inch format imaging trains. This 12nm passband dramatically increases contrast on emission nebulae by rejecting broadband light pollution from city skies, making it an essential tool for urban astrophotography in any 2-inch focuser or filter wheel.

    The 12nm H-Alpha Bandpass: Isolating Emission Nebulae

    Emission nebulae, like the North American Nebula (NGC 7000) or the Heart Nebula (IC 1805), radiate strongly in the red light of ionized hydrogen. The Explore Scientific H-Alpha filter features a narrow 12nm window centered on this wavelength, allowing the faint, detailed structures of the nebula to pass through to your camera sensor while blocking nearly all other light.

    This targeted transmission is the key to defeating light pollution. By rejecting the broad-spectrum glow from mercury and sodium-vapor streetlights, the filter renders the sky background black, causing the nebula's signal to stand out with stark contrast. Faint tendrils and wisps of gas that are completely invisible without a filter suddenly become photographable, even from a suburban backyard.

    Individually Tested: Guaranteed 12nm Performance

    A narrowband filter's effectiveness depends entirely on the accuracy of its bandpass. Explore Scientific ensures this by including an individual test report with every H-alpha filter, verifying its specific transmission characteristics. This isn't just a generic specification sheet; it's a certificate of performance for the exact filter you receive.

    This commitment to quality control guarantees that the filter meets its stated 12nm specification, ensuring you get the light pollution rejection and nebula-enhancing results you expect. It provides the confidence that your equipment is performing optimally for capturing the highest quality astrophotos.

    Choosing a 12nm Filter: When Wider is Better

    While filters with narrower bandpasses, such as 7nm or 3nm, can offer more extreme contrast under the most severe light pollution, they come with trade-offs. The Explore Scientific 12nm H-Alpha filter strikes a critical balance between contrast and signal strength, making it a highly practical choice for many imagers.

    • Shorter Exposures: The 12nm window gathers more photons than narrower designs, allowing you to achieve a strong signal with shorter sub-exposure times. This reduces demands on your mount's tracking accuracy.
    • Less Susceptible to Band-Shift: Very fast optical systems (f/4 or below) can cause wavelength shifts in narrowband filters. The wider 12nm bandpass is more forgiving of this effect, ensuring consistent performance across a broader range of telescopes.
    • Stronger Star Signal: The 12nm bandpass allows for slightly brighter, more natural-looking stars in the final image compared to the pinpricks rendered by ultra-narrowband filters.

  • What is the main advantage of the Explore Scientific 12nm H-Alpha filter for urban astrophotography?

    The primary advantage is its ability to dramatically increase the contrast between emission nebulae and a light-polluted sky. By blocking the wavelengths associated with common streetlights and passing only the 12nm window around the H-alpha line, the filter makes it possible to capture detailed deep-sky images from city and suburban locations.

    How does the 12nm bandpass on this H-Alpha filter affect my exposure times compared to a 7nm filter?

    A 12nm filter allows more light to reach the sensor than a narrower 7nm filter. This means you can typically use shorter sub-exposure times to achieve the same signal level. While a 7nm filter may provide higher contrast, the 12nm filter is more efficient and less demanding on your mount's tracking.

    Can I use the Explore Scientific 2-inch H-Alpha filter for visual observing?

    No, this filter is designed exclusively for astrophotography. The 12nm bandpass is so restrictive that it blocks almost all visible light, and the view through an eyepiece would be extremely dim or completely black. Your eye is not sensitive enough to perceive the faint nebula light it passes.

    How will this 12nm H-Alpha filter perform on the Orion Nebula (M42) from a Bortle 7 zone?

    From a Bortle 7 zone, this filter would be highly effective on the Orion Nebula (M42). It will suppress the bright urban skyglow, allowing you to capture the intricate, filamentary details in the nebula's outer wings that are normally washed out. It will also help control the brightness of the Trapezium star cluster, preventing it from completely blowing out the core of the nebula in your images.

    Is the Explore Scientific 12nm H-Alpha filter a good choice for imaging with a fast f/4 Newtonian?

    Yes, it's an excellent choice. Fast optical systems can cause a phenomenon called "band-shift" with very narrow filters. The wider 12nm bandpass of the Explore Scientific filter is more tolerant of this effect, ensuring that the H-alpha emission line is not shifted out of the filter's passband. This makes it a reliable and efficient option for fast reflectors and astrographs.

    What does the individual test report for the Explore Scientific H-Alpha filter tell me?

    The individual test report is a certificate of quality assurance. It provides a graph showing the exact transmission curve for your specific filter, confirming its central wavelength (CWL) and full width at half maximum (FWHM). This guarantees that your filter performs to the advertised 12nm specification.

  • Filter Type H-Alpha Narrowband
    Size 2-inch
    Bandpass 12nm
  • Explore Scientific Warranty