This H-alpha solar filter system with a 50 mm clear aperture (no central obstruction) can be used on refractors with a focal length of up to 1620 mm. As the LS50FHa has a half-width of approximately <0.75 Angstrom, it offers good contrast for observations of the solar surface as well as for protuberances at the edge.
An adaptor is required to mount the front Etalon filter, which is not included in the delivery. The filter has an M90 thread for screwing onto an adaptor.
The Etalon filter can be tilted for fine tuning using a small wheel.
BF blocking filter: The deflection optics with the eyepiece receiver also accommodate the blocking filter. This filter reduces the brightness of the solar image and is therefore a very important part of the solar telescope, and which must under no circumstances be removed! For purely visual observing, a small blocking filter is sufficient, but for photography a larger one should be selected.
The B1800 blocking filter is very well suited to visual solar observation but can also be utilised for solar photography using cameras with a small sensor chip or which use the APS-C format. For cameras with large sensors, a telescope with a larger blocking filter should be used so that the sensor will be illuminated. For solar photography, we generally recommend so-called planetary cameras which work smoothly with this blocking filter.
Because the LS50 has an estimated bandpass of <0.70 Angstroms it is capable of providing high contrast views of both surface and edge detail. Adding an additional etalon system will reduce the bandpass to ~<0.50 (dependant upon scope) allowing for higher resolution viewing and/or imaging.
