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Baader Planetarium 31mm Round f/2 High-speed H-alpha Filter, Unmounted

SKU: AAFHALHSRD31 MFR: FHALHS-RD31
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Key Features

  • Experience superior H-alpha views with this 31mm narrowband filter, designed for deep-sky astronomy.
  • Achieve maximum contrast on fast astrographs with this high-speed H-alpha filter, unmounted for flexibility.
  • Capture stunning details with this 31mm filter, perfect for CCD imaging at the H-alpha wavelength.
  • Enjoy exceptional light pollution reduction with this specialized Baader Planetarium H-alpha filter.
  • This durable, dielectrically coated 31mm H-alpha filter ensures optimal transmission for clear views.
  • Explore the cosmos with this easy-to-use H-alpha filter, ideal for enhancing your telescope's capabilities.
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Special Order?Estimated to Ship: 09/10/2025
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Review Summary

2019-05-29T16:43:43

Rated 5 out of 5

The perfect mounting cell for eclipse photographers

AstroSolar film is the standard for white light solar filters. This mounting cell has two great advantages for eclipse photographers. The wide flange shades your camera avoiding overheating. The external 3 rubber bumper attachment is easy to remove and replace quickly without disturbing your aim. This is a great advantage for totality in a total solar eclipse. Highly recommended

Robert P.

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Baader Planetarium Filter Specifications

  • Transmission Range

    H-alpha

  • Filter Thickness

    2mm (without Cell)

  • Central Wavelength

    656.3nm

  • AR-coating

    Dielectrically coated, plane optically polished

  • Special Functions

    Maximum Contrast for fast Astrographs

  • Filter Size

    31mm

  • Filter Usage

    CCD, f/2 High-speed, H-alpha

  • Filter Mounted

    Unmounted

  • Type of Filter

    Narrowband

  • Filter Shape

    Round

  • Weight

    0.059kg (0.13 lbs)

About Baader Planetarium Filter

FEATURED REVIEWS

The perfect mounting cell for eclipse photographers

By Robert P.

AstroSolar film is the standard for white light solar filters. This mounting cell has two great advantages for eclipse photographers. The wide flange shades your camera avoiding overheating. The external 3 rubber bumper attachment is easy to remove and replace quickly without disturbing your aim. This is a great advantage for totality in a total solar eclipse. Highly recommended

Discover the transformative power of the 31mm Round f/2 High-speed H-alpha Filter, unmounted, a high-quality and innovative product from the reputable Baader Planetarium. This durable and reliable filter is specifically engineered for the specialized requirements of ultra-fast astrograph optics, including Hyperstar and RASA systems.

Unlike conventional narrowband filters that often result in significant transmission loss due to the strong Central Wavelength (CWL) shift, this high-speed H-alpha filter is designed with a CWL-preshift that perfectly aligns with f/2 to f/3 optics. This unique feature ensures that even in extreme cases, the CWL does not shift out of the Full Width at Half Maximum (FWHM), thereby optimizing the FWHM and delivering maximum contrast.

This effective filter is a game-changer in the field of astrophotography, particularly for high contrast emission nebulae imaging. It is optimized for use with fast optics between f/1.8 and f/3.5, offering a dramatic improvement over regular sets of narrowband filters. Experience the night sky like never before with this innovative filter, designed to capture the hydrogen-alpha emission line in the sun's spectrum with unparalleled clarity and contrast.

Whether you're a seasoned astrophotographer or a beginner in the field, the 31mm Round f/2 High-speed H-alpha Filter, unmounted, is a must-have addition to your astrophotography equipment.

Baader Planetarium Filter Features

  • High-speed H-alpha filter from the reputable Baader Planetarium
  • Specifically designed for ultra-fast astrograph optics, including Hyperstar and RASA systems
  • Features a CWL-preshift to perfectly align with f/2 to f/3 optics, preventing CWL shift out of the FWHM
  • Optimized for use with fast optics between f/1.8 and f/3.5 for high contrast emission nebulae imaging
  • Ideal for observing and photographing the hydrogen-alpha emission line in the sun's spectrum
  • Durable and reliable addition to any astrophotography equipment set

Warranty Information

This product has a limited warranty of 24 months for parts and 24 months for labor.

Key Features

  • Experience superior H-alpha views with this 31mm narrowband filter, designed for deep-sky astronomy.
  • Achieve maximum contrast on fast astrographs with this high-speed H-alpha filter, unmounted for flexibility.
  • Capture stunning details with this 31mm filter, perfect for CCD imaging at the H-alpha wavelength.
  • Enjoy exceptional light pollution reduction with this specialized Baader Planetarium H-alpha filter.
  • This durable, dielectrically coated 31mm H-alpha filter ensures optimal transmission for clear views.
  • Explore the cosmos with this easy-to-use H-alpha filter, ideal for enhancing your telescope's capabilities.

What's in the box:

  • Baader Planetarium 31mm Round f/2 High-speed H-alpha Filter
  • Stackable Filter Box
  • Baader Planetarium 2 Year Limited Warranty