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William Optics WO-Star71 71mm f/4.9 Apo Imaging Refractor

5.0 (1 Reviews) Read Reviews Write Review
Brand William Optics
Part Number A-WO71

Product Info

Manufacturer Description

William Optics is used to churning out excellent telescopes regularly, but they are especially stoked about their latest product. The WO-Star71 imaging telescope provides pinpoint stars at the very edge of a 45mm imaging circle. Take a look at a new production sample photo of the Heart Nebula (IC 1805) / h Persei (NGC 869) / Chi Persei (NGC 884) area in Perseus taken with this telescope!

Key Features

  • 71mm f/4.9 Imaging Refractor Telescope
  • FPL-53 ED glass element for color free apochromatic performance
  • 5 elements in 3 groups (3-1-1- configuration; see photo 2 above. New, unique, patented design - not a conventional objective/flattener/reducer design)
  • Covers 45mm full frame imaging circle
  • 2.5" dual speed R&P focuser
  • Includes mounting rings and Vixen style dovetail
  • Weight = 4.5 lbs / 2.05 kg (OTA only); 5.3 lbs / 2.4 kg (OTA with rings and dovetail)
  • Focuser drawtube travel = 1.38" / 35mm
  • Back focus = 66.4mm from 48mm Canon thread and 91.4mm from drawtube end
  • Optional deluxe soft-padded carry case available separately

Additional Information

  • Focuser drawtube terminates in a male M48x0.75 thread. Telescope comes with a wide M48-Canon EOS adapter ring. Similar rings are available from other supplier for other brands of cameras. Not a conventional 2" focuser tube with locking thumbscrews.
  • Optional 1.25" 90-deg dielectric mirror diagonal sold separately for those wishing to use this as a visual scope (see "Related Products" tab above). This diagonal comes with a custom adapter that connects directly to the M63 female thread on the telescope's focuser tube; you cannot use standard 1.25" diagonals. Telescope cannot reach focus with larger 2" diagonals.
  • The first production run of this telescope had an M65 female thread which was later replaced with a more common M63 thread in subsequent production runs.

Specification for ED Lenses

All William Optics refractor objectives are double tested and inspected by WO at their factory. These telescopes are free of coma and astigmatism. Since all individual lens surfaces are machine coated, sometimes you may notice visual imperfections which will not compromise the optical performance of the telescope. THe dimensions of scratches and points shall not exceed the following values:

  • Scratches - Maximum Width: 0.025 mm
  • Scratches - Maximum Length: 1/4 of total lens diameter
  • Scratches - Maximum Quantity: Three
  • Dots or Spot Points - Maximum Diameter: 0.4 mm
  • Dots or Spot Points - Maximum Quantity: Three
  • Accumulation of Defects - Limited Area: 0.8mm^2
  • Accumulation of Defects - Total Area: 5.8mm^2


5.0 (Based on 1 Reviews) 100% of reviewers recommended this product.
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      User Notes:
      Review by Andrew of El Paso, TX.
      Sep 27, 2015

      5.0 William Optics Star71 imaging (and more!) refractor


      Compact,Quality Lenses,Strong Construction,Accurate,Lightweight,Easy to Use



      I'm an amateur astronomer, and retired. I recently decided to upgrade my equipment, and the scope I decided on was the William Optics Star71. I wanted to able to use the scope for imaging as well as occasional visual observation.

      I use a Canon EOS 20Da for imaging, and standard with the William Optics Star71 is an adapter for the Canon EOS cameras. For imaging I needed nothing else. But since I wanted to be able to use it visually I also bought the William Optics Star71 star diagonal.

      This scope has been the best telescope purchase I have made, but as it turned out I have used it visually much more than for imaging. I routinely volunteer at public outreach star parties and being small this little scope makes it to all of them. I often use 150x (with an X-Cel 2.3mm eyepiece) for planetary use and I've had people comment that the view is better than through the club's 16" Cassegrain! With 150x the 2.3mm is pushing the edge of the envelope, but with longer focal length eyepieces (5mm to 25mm) the resulting image is better than tack sharp! The 2 speed rack-and-pinion focuser is smooth and precise, though at extreme magnification (visually using the 2.3mm eyepiece) there is a slight lateral shift of the image when changing direction. The focuser also has an engraved scale so it can be returned to the same setting when swapping accessories. The Star71 is a 5 element apo which will cover a 45mm image circle, it has a built in field flattener eliminating the need to buy one separately. The Star71 has a sliding dew shield that can be locked with a thumb-screw, and it also comes with an industry standard vixen dovetail bar which is of sufficient length for either visual or imaging use. This scope comes without a finder scope, but at ~350mm focal length one is not really needed.

      I have done little imaging with this scope, but even so to say that I'm pleased with it would be an understatement, I would not hesitate to recommend this scope to everyone.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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      Telescope Aperture 2.80" (71mm)
      Manufacturer William Optics
      Telescope Aperture Up to 80mm
      Telescope Series William Optics Zenith Star