LUNT LS50FHa (0550200) The Double-Stack Etalon Solar-Filter for all LS50FHa Filter and LS60THa Telescopes. LS50FHa Main Filter Transport case Double-Stack Etalon for all LS50FHa filters and LS60THa telescopes. Adding this additional Double-Stack etalon system will reduce the bandwidth to ~<0.55 Angstrom (dependant upon used telescope). So you will have much more contrast and more details on the sun will be visible. Technical data: Aperture: 50 mm No central obstruction Bandwidth double stacked: <0,55 Angstrom Tuning: tiltable Etalon Housing diameter: 95 mm Length: 73 mm Weight: 0.7 kg Front thread: M90x1 female thread Rear thread: M90x1 male thread Without Blocking Filter! Only for use as double-stack filter, or together with a additional available blocking filter. If the filter is used only single stacked together with a optional blocking filter, then the bandwidth is <0.75 Angstrom.