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Cyclops Optics

William Optics Star 71-II f/4.9 APO Astrograph with Bahtinov Mask Cap

Please contact us at for details

William Optics Star 71-II f/4.9 APO Astrograph with Bahtinov Mask Cap

Please contact us at for details
Shipping Weight:
3.90 KGS

Product Description

William Optics Star 71-II is the successor to the well-aclaimed Star 71 imaging APO. Star 71-II is a f/4.9 air-spaced 4-element FPL-53 apochromatic refractor. Star 71-II's 45mm image circle is large enough to cover your 35mm full frame DSLR camera and provides pinpoint stars from edge to edge across the field of view. Focuser drawtube terminates in M48 thread which connects directly to DSLR T-ring, cooled CCD or filter wheel directly.

Star71-II Package Includes

  • Star71-II f/4.9 Astrograph
  • William Optics' patented innovative Bahtinov Mask Cap
  • 2.5" 1:10 rack & pinion focuser
  • 360º camera angle adjuster
  • A set of guide scope rings
  • A pair of mounting rings
  • Vixen style dovetail bar
  • Retractable lens shade


  • M48 to Canon EOS T-mount adapter 
  • M48 to Nikon T-mount adapter 

Star71-II Design Highlights

  • 71mm f/4.9 4 elements air-spaced objectives aprochromatics
  • Includes 2 FPL-53 ED fluorite elements
  • 4 elements in 3 groups (2-1-1 configuration, patented design)
  • Precision optics with STM coating
  • Very sharp image with great colour correction across the 45mm image circle
  • Designed specially for astrophotography


Cyclops Optics' Exclusive Fine Tuning Service

We offer fine tuning service for the telescopes to provide a smoother screws control and grant the telescope a premium quality touch. The fine tune service costs HK$400 (US$50). It's now waived for time-limited period.

Star71-II User Gallery

M42 by Jerry Huang
IC348 by Jerry Huang
M8 & M20 by Jerry Huang



Optical system 4 elements with 2 FPL-53 ED fluorite elements
(2-1-1 patented configuration)
Aperture 71 mm
Focal length 350.2 mm
Focal ratio f/4.9
Image circle

45 mm

Back focus 71.3 mm from M48 thread
Light gathering power 103x
OTA length

440 mm (fully extended)
484 mm (contracted)


2.05 kg (OTA only)
2.40 kg (with rings and dovetail bar)


7 days no question asked return if due to material or workmanship defects

2 years from William Optics

Cyclops Optics Ltd. is an authorised dealer of William Optics' products.


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