Product Review

For terrestrial viewing with a refractor or Cassegrain telescope, use of a correct-image (or image erecting) prism diagonal may be desirable. The image through the eyepiece image will appear upright and non-reversed, matching the naked-eye orientation. So a correct-image diagonal is essential for terrestrial viewing with the above telescope types and is useful for astronomical viewing for those that prefer to have the view through the telescope match the naked-eye orientation. Note that the 45-deg correct-image diagonal requires 5/8" more focus travel than typical diagonals. Diagonals are not recommended for use in reflector telescopes.