William Optics

Used RedCat 51mm f/4.9 with Handlebar

SKU: U2406-SC-L-RC51

  • Sale
  • $599.95
  • Regular price $865.00

See It In Person - On Display In Our Showroom!

Qualifies for Free Ground Economy Shipping (CONUS Only)

Not Returnable Please note that used items are not returnable.

Condition: This is a RedCat 51 is in excellent condition.  The optics are clean as well as the body. 

The scope comes complete, as you see it in the photos, and comes in its original soft-sided foam-lined case. This also includes a handlebar. 



Probably the very sharpest 250mm camera lens you will find!

  • Newest version (including camera angle adjuster, cat paw scope clamp, DSD dovetail bar, and focus tensioner)
  • 51mm quadruplet ED APO f/4.9 (250mm fl)
  • FPL53 & FPL51 glass 
  • 3.2 lbs tube weight.
  • >43mm imaging circle with a flat field edge to edge for full-frame sensors
  • Dual Vixen and Arca Swiss Dovetail
  • M48 thread to accept wide t-rings/t-mounts


The best value, highest quality 250mm lens you will find for your camera.

51 mm lens, in a sleek Petzval design, using Synthetic Fluoride (FPL53 and FPL51) glass for a full-frame flat field image. The optical quality provides exceptional performance at a fast focal ratio of f/4.9. 

Filter Adapter allows use of 48mm filters. Focusing is made easy with a bahtinov mask integrated into the lens cap. 


Aperture 51 mm (2")
Camera/Eyepiece Connection Male M48x0.75
Dawes Limit 0.46 arcseconds
Focal Length 250 mm
Focal Ratio f/4.9
Glass Type FPL-53 and FPL-51
Highest Useful Magnification 102x
Light Gathering Power 53x
Limiting Magnitude 12.3
Optical Design Petzval
Tube Color Red
Tube Diameter 51mm
Tube Weight 3.2 lbs
Dew Shield Outer Diameter (for soar filter sizing) 80.5mm


  • RedCat 51mm Telescope
  • Bahtinov Mask Cap
  • 210mm Dovetail
  • Upgraded Mount Ring (with cat paw logo)
  • Soft Carry Case