Coronado 90mm Adapter Ring

Coronado 90mm Adapter Ring is required to double stack an SME90 external primary Etalon, double stacking an original 90mm Coronado or Coronado II telescope such as an SMT90. Telescope and double stacking filter sold separately.

Reduces original 0.7 angstrom bandpass of the hydrogen-alpha telescope to 0.5 angstrom, dramatically increasing visibility of surface detail such as granularity and active regions on the surface of the Sun.