Telecentricity with a generously dimensioned entry opening with
negative lens group, with 2″ (50.8mm) threads on both sides – incl.
T-2 adapter and 2″ I/A reversing ring as standard;
46mm free opening in connection to the H-alpha filter, thus also
suitable for SolarSpectrum Research Grade Filter ;
Extra-long working distance of 250 mm for optimized focal lengths
reduction with telecompressors or for binocular observation ;
Aplanatic, with 3x focal length extension and free of
Field of view curvature – provides f/30 on telescopes with f/10 ;
Specially calculated and manufactured for the H-alpha wavelength, with
99% Strehl (99% definition brightness at 656.3 nm) depending on
from the telescopic system used ;
Even at calcium-K (396nm) it still provides diffraction-limited imaging
with approx. 80% Strehl