For all SolarSpectrum H-alpha filters - with thread 2 "male to 2" male.
SolarSpectrum H-alpha filters require parallel light with a beam path of at least f / 30. This is achieved by extending the focal length with a telecentric system. Due to the extension of the focal length, the complete sun is no longer visually visible with many telescopes when using eyepieces with focal lengths from 30 to 35 millimeters.
The two SolarSpectrum telecompressors are mounted directly onto the filter on the eyepiece side and reduce the previously extended focal length by a factor of 0.4 or 0.7, with the result that the entire sun disc with protuberances is now visible again.
For photographic applications, the telecompressor is used to adjust the focal length to poor seeing conditions and / or to enlarge the field of view.
Working distance : 110 millimeters (distance to the camera sensor), optimized for videography and imaging of the entire sun.