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

Now with new-generation etalons — every unit individually measured at 656.28nm on Lunt's precision metrology equipment. Every specification is verified, not estimated.

The LS40THa Premium Kit delivers the finest double-stack performance available in any 40mm solar telescope. The front-mounted LS40FHa double-stack filter adds a second 0.35Å tilt-tuned etalon to the optical path, placing two etalons of equal specification in series. Combined system bandpass: <0.25Å — tighter than any other double-stack combination in the Lunt range, and a level of chromospheric contrast no competitor in this aperture class can match.

This is serious H-alpha equipment in a genuinely portable package. At 2.6 pounds with a 10:1 dual-speed rack-and-pinion focuser, a 7.2–21.5mm zoom eyepiece, and an extended 6" Vixen dovetail for balanced mounting with the DS filter in place, the Premium Kit is configured for the observer who wants the maximum from 40mm aperture — at the eclipse site, in the field, or at home.

What You'll See

At <0.25Å combined bandpass, the chromosphere reveals structure invisible at single-stack bandwidths. Plage boundaries sharpen into defined cellular networks. Filaments resolve into complex multi-strand structures with dark cores and distinct edges. Active regions display the full depth of their magnetic architecture. Prominences show internal threading and flow patterns from base to tip that single-stack instruments render as smooth, featureless arcs. The chromosphere stops being a texture and becomes a landscape.

The 7.2–21.5mm zoom eyepiece lets you scan full-disk context at 19x, then push in to 56x on active regions without changing glass — critical when conditions are changing and solar features are evolving faster than eyepiece swaps allow.

Why This Package

The LS40FHa Double Stack filter is included. The 10:1 dual-speed R&P focuser provides the micro-adjustment precision that sub-quarter-angstrom observing demands. The 6" Vixen dovetail provides the extended rail length to balance the system with the DS filter mounted. Every unit is individually assembled, bench-tested, and monochromator-verified before leaving Tucson.

Package Includes

• LS40THa OTA: 40mm aperture, 400mm FL, f/10. Front-mounted tilt-tuned etalon, 0.35Å bandpass. Full unobstructed aperture. Dedicated H-alpha solar telescope.
• LS40FHa Double Stack: 40mm front-mounted tilt-tuned etalon. Combined system bandpass <0.25Å — two 0.35Å etalons in series. No central obstruction. Includes adapter. ~1 lb.
• B600 Blocking Filter: 1.25" diagonal housing, 6mm clear aperture. Optimised for LS40 focal length and image scale.
• 1.25" R&P Focuser (10:1 dual-speed): CNC-machined aluminium/brass. Integrated brake with variable drag. Rotatable. 6–8 lb capacity.
• SunLock Solar Finder: Red dot projection onto glass reticle. Internal 3-point alignment screws. Red anodised aluminium.
• 6" Vixen Dovetail Plate: 150mm length, black anodised aluminium. Three 1/4-20 tapped holes. Extended rail for balanced mounting with DS filter.
• Hard Case: Silver aluminium, 18.5" x 10.5" x 7". Custom-fit foam insert.
• 7.2–21.5mm Zoom Eyepiece: 7 elements/4 groups. 0.1% AR coatings. 15mm eye relief. 53°–40° FOV. Near-parfocal.

Key Specifications

• Aperture: 40mm, full unobstructed
• Focal Length: 400mm
• Focal Ratio: f/10
• Etalon Type: Dual front-mounted tilt-tuned (LS40THa + LS40FHa)
• Single Stack Bandpass: 0.35Å — individually verified
• Double Stack Bandpass: <0.25Å combined — two 0.35Å etalons in series
• Blocking Filter: B600 (6mm clear aperture)
• Focuser: 1.25" CNC R&P, 10:1 dual-speed, integrated brake, rotatable
• Eyepiece: 7.2–21.5mm zoom (19x–56x on LS40THa)
• Weight: ~2.6 lbs OTA + ~1 lb DS filter
• Telescope Type: Dedicated H-alpha solar — daytime use only