Lunt LS40FHa Front Mount 40mm Double Stack Solar Filter

Lunt LS40FHa Front Mount 40mm Double Stack Solar FilterLS40FHa 40mm Front Mount Double Stack Solar Filter The double stack upgrade for the Lunt LS40THa series. Two 0. 35 etalons in series the tightest combined bandpass in the Lunt range. Now with new generation etalons every unit individually tested on Lunt's precision metrology equipment. Every specification is verified, not estimated. The LS40FHa is a 40mm aperture front mounted tilt tuned etalon designed for two purposes as a double stack upgrade for

• LS40FHa — 40mm Front-Mount Double Stack Solar Filter The double-stack upgrade for the Lunt LS40THa series. Two 0.35Å etalons in series — the tightest combined bandpass in the Lunt range.

  Now with new-generation etalons — every unit individually tested on Lunt's precision metrology equipment. Every specification is verified, not estimated.

  The LS40FHa is a 40mm aperture front-mounted tilt-tuned etalon designed for two purposes — as a double-stack upgrade for the Lunt LS40THa dedicated 40mm solar telescope series, or as a standalone H-alpha solar filter for a compatible customer-supplied refractor.

  As a double-stack filter for the LS40THa: The LS40FHa adds a second 0.45Å etalon to the optical path, placing two etalons of equal specification in series with the LS40THa's own front-mounted etalon — delivering a combined system bandpass of <0.29Å. This is the tightest combined bandpass available in any Lunt double-stack configuration. Because both etalons are front-mounted tilt-tuned at 0.45Å — rather than pairing a front-mount filter with an internal pressure-tuned etalon — the in-series result is tighter than larger double-stack systems. At <0.29Å, chromospheric detail that single-stack instruments at this aperture cannot resolve becomes visible: plage boundaries sharpen into cellular networks, filaments reveal dark cores and multi-strand structure, and prominences show internal threading from base to tip.

  As a standalone H-alpha filter for customer refractors: The LS40FHa can be used on a compatible customer-supplied refractor as a standalone front-mounted H-alpha filter. A Lunt blocking filter must be used at all times — this is a safety requirement. If you are looking for a complete standalone package including a blocking filter and adapter, Lunt offers complete front-mounted filter packages that include both at:
  luntsolarsystems.com/collections/front-mounted-etalon-systems

  Installation requires no tools and no factory visit. A Lunt blocking filter is required for safe operation — the LS40FHa is not a standalone safety device.

  Specifications

  • Model: LS40FHa
  • Optical Aperture: 40mm — no central obstruction
  • Tuning: Tilt-tuned
  • Single Etalon Bandpass: 0.45Å — individually verified
  • Combined System Bandpass: <0.29Å — two 0.45Å tilt-tuned etalons in series
  • Compatible With: LS40THa series (DS); compatible customer refractors (standalone)
  • Focal Length: 400mm (unchanged)
  • Blocking Filter Required: Yes — sold separately (B500 or B600 recommended)
  • Weight: ~1 lb (~0.4kg)
  • Storage: Aluminium hard case with fitted foam (optional)