Don’t put a standard-issue diagonal into a high-quality refractor or Cassegrain telescope or you’ll be losing 10% or more of the light collected by the telescope’s optics. Use an Orion Enhanced diagonal instead. Their lab-tested enhanced aluminum coatings reflect 97% of the inbound light to your eyepiece, for brighter images compared to standard diagonals. Orion’s beautifully machined and anodized aluminum housings feature machine-threaded baffles for high contrast and nonmarring compression ring collars for securing the eyepiece. The diagonal’s nosepiece barrel is threaded to accept 1.25″ filters. Endcaps included.
This diagonal requires approximately 9cm inward focus travel relative to an eyepiece’s focus position without the diagonal. Diagonals are not suitable for use with Newtonian reflector telescopes due to insufficient focus travel.