The New Lunt Solar LS50THa Hydrogen-alpha Solar Telescope LS50THa/B400PT Lunt Solar Systems is excited to announce our new 50mm Pressure Tuned dedicated Hydrogen-alpha telescope, the LS50THa! This new solar telescope is a refractor-based system with a 50mm aperture and an internal-mounted etalon with Pressure Tuner adjustment. This system allows for a <0.75 Angstrom band pass. Specifications: (single stacked) Type: Single Interference Etalon Tuning: Internal Pressure Tune (Doppler True Tuning) Aperture: 50mm Focal Length: 350mm F Ratio: F7 Bandpass: <0.75 Angstroms @ 656nm Focuser: Helical Focuser Mounting: Integrated clamshell style with 1/4-20 tapped base Color: Pearl White with Black and Red accents Diagonal: B400 Blocking Filter An optional and especially designed LS50C Compact double stack filter is also available at additional cost. The LS50C allows you to lower the bandpass to <0.5 Angstroms, which gives you much more surface detail. The filter threads directly onto the LS50THa.