The bandwidth of H-alpha systemscan be reduced by so-called "double-stacking". A smaller bandwidth provides much more contrast at the solar surface, thereby many more details will become visible. Double-stacking with a bandwidth of only <0.5 Angstrom is also possible at the LS50THa telescopes. Therefore Lunt Solar Systems has especially designed this LS50C double-stack filter in compact housing. The filter threads directly onto the LS50THa telescopes. Technical data: Aperture: 50 mm Bandwidth: <0.5 Angstrom Tuning: mechanical tilt-tuning only usable together with a LS50THa telescope!