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Lunt 50mm Ha Etalon Filter
Lunt 50mm Ha Etalon Filter
Lunt 50mm Ha Etalon Filter

Lunt 50mm Ha Etalon Filter

by Lunt Solar Systems
SKU LSS-LS50FHaP
$1,145.00 USD - $1,145.00 USD
$1,145.00 USD
$1,145.00 USD - $1,145.00 USD
$1,145.00 USD
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  • 50mm Clear Aperture
  • Tilt-Tuned Hydrogen-Alpha Etalon
  • Verified Bandpass of <0.4Å
  • Enables <0.28Å Double-Stacking on LS60MT
  • Front-Mount Filter Design
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  • Description
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  • Lunt 50mm H-alpha Etalon Filter

    The Lunt 50mm Ha Etalon Filter is a 50mm aperture, front-mounted, tilt-tuned solar filter with a verified bandpass of less than 0.4Å. It is designed as a direct-fit double-stack upgrade for the Lunt LS60MT telescope, combining with the scope's internal 0.45Å etalon to achieve an ultra-narrow system bandpass of less than 0.28Å for maximum contrast on solar surface details.

    Double-Stacking the LS60MT: Achieving a <0.28Å Bandpass

    This filter's primary purpose is to enhance the Lunt LS60MT Modular Telescope. By mounting the 50mm LS50FHa to the front of the LS60MT, its <0.4Å etalon is placed in series with the telescope's internal <0.45Å pressure-tuned etalon. This combination narrows the final bandpass to less than 0.28Å, dramatically increasing contrast and revealing fine structures within the Sun's chromosphere, such as filaments and active region plages, that are subtle or invisible in a single-etalon system. The upgrade is user-installable with no factory service required and is easily removed for nighttime astronomy.

    Standalone Solar Filter: A 50mm, <0.4Å Front Etalon for Refractors

    Beyond the LS60MT, the LS50FHa can serve as a standalone 50mm H-alpha filter for a compatible, customer-supplied ED refractor. The tilt-tuning mechanism allows you to shift the bandpass off the central H-alpha line, helping to highlight Doppler-shifted details like eruptive prominences. When used in this configuration, a crucial trade-off is the requirement for an appropriate Lunt blocking filter, which must be purchased separately and matched to your telescope's focal length to ensure safe viewing and proper system performance.

  • What is the main advantage of double-stacking my Lunt LS60MT with the LS50FHa filter?

    Double-stacking your LS60MT with the Lunt 50mm Ha Etalon Filter narrows the system's bandpass from ~0.45Å to under 0.28Å. This significant increase in spectral resolution dramatically boosts contrast on the solar disk, making surface details like plages and the intricate structure of filaments appear much more defined.

    Can I use the Lunt 50mm Ha Etalon Filter on a telescope other than the LS60MT?

    Yes. The LS50FHa can be used as a standalone H-alpha filter on a compatible customer-supplied ED refractor. However, to create a safe and functional solar telescope, you must pair it with a correctly sized Lunt blocking filter installed at the eyepiece end of your telescope.

    How does the LS50FHa's tilt-tuning work?

    The Lunt 50mm Ha Etalon Filter uses a mechanical tilt mechanism to slightly angle the etalon relative to the incoming light. This angle shifts the filter's central wavelength, allowing you to fine-tune the view for the best contrast or to study features that are Doppler-shifted, such as fast-moving ejecta in a solar flare.

    Do I need to send my LS60MT to the factory to install the LS50FHa?

    No. The LS50FHa is designed for easy, at-home installation. It threads directly onto the front of the Lunt LS60MT telescope, requiring no special tools or factory service. This allows you to easily switch between single-stacked, double-stacked, and nighttime configurations.

    How will the LS50FHa help me see solar prominences versus surface detail on the Sun?

    While a single-stack system shows prominences well, the high-contrast view from double-stacking with the LS50FHa excels at revealing faint, low-contrast surface details. The bright, web-like patterns of plages around sunspots become significantly more visible with the <0.28Å bandpass.

  • SKU LS50FHaP
    Aperture 50 mm
    Filter Type Front-Mount Hydrogen-Alpha Etalon
    Bandpass (Single) < 0.4Å
    Tuning Tilt-Tuned
    Primary Compatibility Lunt LS60MT (as double-stack)
    Bandpass (Double-Stacked on LS60MT) < 0.28Å
    Weight 1 kg (2 lb)
    Blocking Filter Required, sold separately (B600 up to 540 mm FL visual; B1200 up to 1,080 mm; B1800 up to 1,620 mm)
    Wavelength 656.28 nm

    • Lunt 50mm Ha Etalon Filter × 1 Aluminium hard case with fitted foam

      × 1

  • Lunt Solar Systems 5-Year Warranty