William Optics

50mm Erecting Finder Scope

  • Sale
  • Regular price $250.00

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New from William Optics! A unique 50mm finder OTA with a 90-degree erecting prism diagonal with helical focuser providing a right angle correct image. Use many standard 1.25" eyepieces* to get the magnification and field of view you like! Available in a choice of 3 colors to complement your William Optics or other scope.

Optical Features

  • Fully multi-coated 50mm f/4 (focal length = 200mm) achromatic objective
  • 90-deg high-quality erecting prism diagonal included
  • Provides 10x magnification with a 20mm eyepiece or 8x with a 25mm eyepiece; will provide 5.7 deg field of view with 24mm, 50-deg AFOV reticle eyepiece (Eyepieces sold separately)

Mechanical Features

  • 1.25" diagonal features helical focusing
  • Diagonal / eyepiece are rotatable
  • White powder painted with excellent fit and finish that are the hallmark of every William Optics product

Finder Bracket

  • Not included; sold separately

* Note that not all eyepieces will reach focus in this or any other finder due to the limited focus travel range. Finding a compatible eyepiece that reaches focus may require some trial and error. This is an issue with any finder/spotting scope/guidescope that can accept external eyepieces, and not just with this item.


  • Tube diameter = 54.6mm (2.15")
  • Dewshield diameter = 58.1mm (2.29")
  • Tube weight (without eyepiece) = 21.9oz (620g)
  • Included: 90 degree erecting image prism and 58mm dew shield
  • Type: Angled
  • Objective: High Quality 50mm
  • Deg. field of view: 5.7
  • Eyepiece Compatibility: 1.25" eyepieces
  • Color: Powdered white with red, blue, or gold accents
  • Coatings: Fully multi-coated
  • Aperture: 50 mm
  • Length: 220 mm
  • Model Number:  M-F50IIRD
SKU: M-F50IIGD + E-WA24 + E-IR