William Optics 90 ° Erecting Diagonal for RedCat (1.25")

William Optics 90 ° Erecting Diagonal for RedCat (1.25")

Due to high demand and global product shortages due to the pandemic, please call for availability.

The William Optics RedCat 90° erecting prism is specifically built for the RedCat 51 astrophotography scope. Built to provide a correct image for visual use.

Employs a high quality erecting prism with Red anodized plate. The complete housing is made by 6061T Aluminium by CNC.

Very useful for daytime observations - convert your RedCat into a spotting scope.


  • Image erecting BAK4 prism with anti-reflection coating
  • High accuracy and high light transmission prism
  • 1.25” barrel for any 1.25” eyepieces
  • Internally matte blackened and threaded for no internal stray light reflection
  • Entirely aluminum, red anodized


  • Prism: &90deg; Amici roof-prism, correct-image
  • Eyepiece interface: 1.25", with compression band
  • Weight: to be determined