Lunt LS100FHa Solar Filter

(1 customer review)


  • 100mm front-mounted minimally obstructed hydrogen-alpha filter for use on a wide range of telescopes!
  • Connect the Lunt LS100FHa to your telescope with the appropriate adapter (sold separately), or use it to double-stack on an existing Lunt 100mm solar telescope or filter for a ~<0.5A band pass!
  • Choose the appropriate LS100FHa and blocking filter for your telescope’s focal length and focuser size.

Required Accessories: Typically an adapter plate will be required to attach a Lunt Solar Filter to the front of a customer-supplied telescope. These adapters are in stock for the more common user scopes, but can be custom-made to your specific requirement.  An adapter is needed to add a LS100/DS module to a LS100FHa.

Please Note: If this product shows “Available on Backorder” and you would like to “get in line” by placing an order with a 10% deposit, send us an email. A member of our staff will contact you with lead times and deposit information.


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LS100FHa Solar Filter

The Lunt LS100FHa Solar Filter is a 100 mm aperture with a Root 3 non-centralized obstruction  integrally tuned etalon for use on a customer-supplied refractor.

The standard system includes the B600 blocking filter, which provides full disk images on telescopes with up to 540 mm of focal length. Larger blocking filters suitable for longer focal length telescopes are also available options.

These Hydrogen-alpha filters are designed to retrofit (adapters required) the customer-supplied telescope for use during the day. They are easily removable so that the scope can continue to be used for night observing.

LS100FHa Solar Filter systems include a front-mounted filter and a rear mounted 2″ or 1.25″ blocking diagonal. Choose the blocking filter that best suits your telescope and your focuser size:

  • B600 –   Up to 540 mm focal length, offered in 1.25″ or 2″ diagonal
  • B1200 – Up to 1080 mm focal length, offered in 1.25″ or 2″ diagonal
  • B1800 – Up to 1620 mm focal length, offered in 1.25″ or 2″ diagonal
  • B3400 – Up to 3060 mm focal length, offered in 2″ straight-through tube

Because the LS100FHa Solar Filter has an estimated bandpass of <0.70 Angstroms it is capable of providing high contrast views of both surface and edge detail. Adding an additional etalon system (double-stacking) will reduce the bandpass to ~<0.50 (dependent upon scope) allowing for higher resolution viewing and/or imaging. The part number LS100FHa is offered for this purpose or for those who already have a Lunt blocking filter. A Lunt blocking filter must be used with Lunt Ha filters at all times.

LS100FHa Specifications: (single stacked)

  • Optical Aperture: 100 mm
  • Etalon: Internal <0.7 Angstrom
  • Tuning: Tilt
  • Storage: Aluminum finished hard case with fitted foam
  • Weight: 8 lb

Find information about the Sun from NASA

1 review for Lunt LS100FHa Solar Filter

  1. Dan M.

    Have had the LS100FHa under the sun for several sessions and it makes everything POP. Contrast and detail are enhanced and pleasing to observe even in this solar minimum.
    That was back before all the action of this Solar Maximum started.

    Fast forward to 2023 and the LS100FHa has been a performer second to none with my LS100THa.
    I never observe without the DS installed.
    Simple setup, screw it on the scope and I find if I rotate it back 1/4 turn from being snug and apply very little tilt the ghost image is out of the view and a detailed tuned image is available in the binos with the Pressure Tuner adjustment.
    I’ve found this filter to be a set and forget, and adjust the tune with the Pressure Tuner once it’s in place, repeats every time.
    Proms are bright , structured and detailed against a velvet black field , absolutely no red glow, Filaments look 3D and stand out against the disk, very dark with structure.
    Large sunspots will dominate the AR regions with all their swirling wisps of detail all around the area.
    The edge of the disk is lined with Spicules , sawtooth like all around the rim on most days.
    The AR regions are a lighter color than the rest of the disk but a Flare stands out white hot in the ARs and on many occasions I’ve noticed movement in Flares and Surge Proms in real time.
    The solar surface is alive with detail everywhere and will provide ever changing observing opportunities with the right equipment.
    The LS100FHa is a worth while investment to provide this excellent visual experience.

    Dan M “BigDob 24”

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