Lunt 40mm Double Stack Filter for LS40THa

• Preorder notice: ships 30–60 days after checkout (estimated window)

• Purpose-built LS40FHa front etalon to double-stack your Lunt 40 mm dedicated H-alpha telescope for a serious contrast boost

• No central obstruction and integral tilt tuning maintain even illumination and let you precisely dial features on-band

• Tighten your system from an estimated <0.70 Å (single stack) down to ~<0.50 Å (double stack) for finer filaments, mottling, and plage detail

• Blocking filter required for safe operation (Lunt BF, matched to your setup; sold separately)

• Drop-in upgrade that does not change the telescope’s focal length (400 mm remains unchanged)

• Lightweight, field-friendly design (~1 lb)—ideal for travel and quick outreach setups

• Store it with your scope: fits the optional LS40 aluminum hard case with fitted foam

Specifications

• Model: LS40FHa Double Stack Solar Filter (for Lunt 40 mm dedicated H-alpha telescopes)

• Optical Aperture: 40 mm (front-mounted; no central obstruction)

• Bandpass (effective, double-stacked): ~<0.50 Å

• Bandpass (single-stack reference): <0.70 Å (host system prior to DS)

• Tuning: Tilt (integrally tuned)

• Telescope Focal Length (unchanged): 400 mm

• Weight: ~1 lb (~0.4 kg)

• Storage: Fits optional LS40 aluminum hard case with fitted foam

• Safety Requirement: Use only with a Lunt Blocking Filter appropriate to your system

What’s in the Box?

• Lunt LS40FHa 40 mm Double Stack Etalon Unit

Notes: A Lunt Blocking Filter (BF) is required and sold separately. This DS filter is designed exclusively for Lunt’s dedicated LS40 H-alpha telescopes.