William Optics Star71-II 71mm f/4.9 Apo Imaging Refractor / Astrograph: Blue # A-WO71-II

Our Price: $1,198.00
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Our Product ID: T-WO-STAR71-II-B
Manufacturer SKU: A-WO71IIBU
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William Optics Star71-II 71mm f/4.9 Apo Imaging Refractor / Astrograph: Blue # A-WO71-II

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Product Details

NEW: Latest version with patented Bahtinov Mask Cover, Guidescope Rings, and Free Carrying Case

The new William Optics Star71-II imaging telescope replaces the venerable first generation of this telescope introduced in 2014. The Star71 is an excellent, portable, high-quality apochromatic astrograph with a built-in flattener for the astro-imaging enthusiast.

How does this differ from the 1st generation Star-71 telescope?

  • Mechanically, the two scopes are virtually identical.
  • Optically, their performance is identical too. The key difference is that the first generation Star-71 had a five-element design out of which only one element used FPL-53 ED glass. This second generation has a new four-element design using two FPL-53 ED lens elements. William Optics retained the same optical design parameters and performance, but the new design is much easier to collimate during assembly.
  • The new tube features a Vixen-style dovetail base for attaching finder/guider brackets.
  • A soft padded carry case is now included as a standard accessory. It was sold separately earlier.
This scope is ultimately designed for astronomers who want the best results in photographic/CCD imaging. The WO-Star71 imaging telescope provides pinpoint stars at the very edge of a 45mm imaging circle.

Key Features

  • 71mm f/4.9 imaging refractor telescope with 350mm focal length
  • Two FPL-53 ED glass elements for color free apochromatic performance
  • 4 element design with built-in field flattener (3 groups, 2-1-1- configuration; 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 soft padded case, mounting rings, finder/guidescope bracket, and Vixen-style dovetail rail
  • Weight = 4.2 lbs / 1.91 kg (OTA only); 4.85 lbs / 2.2 kg (OTA with rings and dovetail)
  • Focuser drawtube travel = 1.38" / 35mm

Additional Information

  • The focuser drawtube terminates in a male M48x0.75 thread so you can use wide 48mm T rings to attach compatible DSLR cameras to this scope (T rings sold separately). Note that this a not a conventional 2" focuser tube with locking thumbscrews.
  • An optional 1.25" 90-deg dielectric mirror diagonal is available separately for those wishing to use this as a visual scope. This diagonal comes with a custom adapter that connects directly to the M63 female thread on the telescope's focuser tube. You cannot attach standard 1.25" diagonals and the telescope cannot reach focus with larger 2" diagonals.
  • The Petzval element does NOT move with the focuser. It remains stationary within the tube. As as long as you attaining focus on the sensor plane, it will "automatically" reach the correct spacing, since that is the location of the focus (for objects at infinity), and does not change relative to the Petzval element.

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 minor 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

Useful Resources

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