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 a focal length extension with a telecentric systems. Due to the focal length extension of many telescopes when using eyepieces with focal lengths of 30 to 35 millimeters, the entire sun is no longer visually visible.
The two SolarSpectrum telecompressors are mounted on the eyepiece side directly on the filter and reduce the previously extended focal length by a factor of 0.4 or 0.7, with the result that the entire solar disk with protuberances is now visible again.
For photographic applications, the telecompressor is used to adjust the focal length to possibly poor seeing conditions and / or magnification of the recording field.
Working distance : 74 mm (distance to the camera sensor), optimized for videography and imaging of the entire sun. 16 mm diameter corrected image field.