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Cyclops Optics

William Optics GT71 71mm f/5.9 Triplet APO 20th Anniversary Limited Edition


William Optics GT71 71mm f/5.9 Triplet APO 20th Anniversary Limited Edition

Shipping Weight:
5.00 KGS
Limited Edition sold out
Free Shipping

Product Description

William Optics GT71 APO is a f/5.9 air-spaced triplet FPL-53 apochromat. This package includes a 0.8x Flat6A-81 reducer cum flattener specially designed for GT71 to transform it into a f/4.7 imaging APO covering full frame sensor.

GT71 20th Anniversary Limited Edition Package Includes

  • GT-71 APO 3-element objective with FPL-53 extra low dispersion glass
  • 2.5" V-Power crayford zero image shift focuser
  • Flat6A-71 0.8x reducer flattener 
  • Canon T-mount and spacer 
  • Dual mounting rings with Vixen style dovetail bar
  • 2" to 1.25" adapter with brass compression ring
  • Retractable lens shade
  • High quality custom-made aluminium case with lock

GT71 Design Highlights

  • 71mm f/5.9 triplet air-spaced objectives APO
  • Includes 1 FPL-53 fluorite element
  • Very sharp image with excellent colour correction
  • Precision optics with fully multi-coated lenses using super-high transmission (STM) coating on all surfaces
  • Designed for astrophotography and visual observation

Free High Quality Aluminium Case Designed Specially for GT71 20th Anniv. Limited Edition


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.


Optical system Air-spaced triplets with 1 FPL-53 fluorite element
Aperture 71 mm
Focal length 420 mm
Focal ratio f/5.9
Image circle

40 mm

Back focus

64mm with Flat6A-71
66-86 mm with Adjustable Flattener Reducer IV

Resolution 1.62 arcseconds
Limiting magnitude 11.1
Light gathering power 103x
OTA length

325 mm (contracted)
427 mm (fully extended)

Weight 2.2 kg

Free shipping applies

United States, S. Korea, Japan, Malaysia, Philippines, Singapore, Hong Kong, Taiwan, Indonesia, Australia, New Zealand, Germany, France, Switzerland, Sweden, Denmark, Netherlands, United Kingdoms and others.

Via FedEx International Economy. Arriving in 1-5 working days.


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

2 years manufacturer's warranty from William Optics

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

Quality Control

Scratches   Width no more than  0.025 mm
 Total length no more than  1/4 of total lens diameter. No more than 3 individual scratches
 Dots or spots   Diameter, no more than  0.4 mm
 Quantity no more than  3
 Accumulation of defects   Limited area  0.8 mm2
 Total area of scratches and points no more than  5.8 mm2







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