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Cyclops Optics

William Optics Gran Turismo GT81 II


William Optics Gran Turismo GT81 II

Shipping Weight:
7.00 KGS
Accepting order now!

Product Description

GT81 Latest & Most Current Version: GT81-IV

Innovative Bahtinov Mask Cover (Patented) & New Dovetail Plate included!

The new 2018 GT81 three-element super APO offer superb quality for imaging and visual use at an affordable price!From the pristine white finish on the CNC to the elegant gold trim which has more than just good looks...

Optically Unbeatable

  • Triplet air-spaced objective (FPL-53) in adjustable CNC machined ultra high precision lens cell
  • Extremely sharp
  • Excellent color correction
  • Each lens is Fully Multi-Coated with a special super-high transmission coating (STM Coating) on all surfaces
  • This F/5.9 lens is ideal for astrophotography

2.5” R&P Focuser

  • 2.5” R&P Ultra robust focuser with 1:10 dual speed: a treat to use during astrophotography. No image shifting!
  • Heavy duty: perfect for your accessories

Simply Beautiful Finish

  • Pure William Optics quality fit and finish: powder-painted white CNC-machined aluminum tube, gold trim finish, retractable dewshield, dewshield cap
  • Top quality anodizing
  • Very compact for carrying on flights

Attention to Details

  • 2" & 1.25" adapter included in the price
  • Anti-marring brass compression rings
  • Though you will never need it, you have a 2-year warranty from WO, and the certainty that we will be there to assist you even beyond that, if you need!

Standard Package:

  • WO GT81-II
  • OTA Mounting Rings
  • Guiding Rings
  • New Dovetail Plate
  • 2.5” R&P Focuser
  • Innovative Bahtinov Mask Cover (Patented)
  • Soft Carry Case
  • Two-year, no fuss warranty and constant customer service!

Optional Accessories:

  • M63 -2” Rotolock
  • 1.25” Rotolock
  • All New 50mm/F4 Rotolock Guide scope
  • New Full frame x0.8 Flattener

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 81 mm
Focal length 478 mm
Focal ratio f/5.9
Image circle

44 mm with Flat6A-II (97% full frame illumination)

Resolution 1.43 arcseconds
Limiting magnitude 12.2
Light gathering power 134x
OTA length

400 mm (fully extended)
390 mm (contracted)

Weight 3.84 kg with tube rings and dovetail mount



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

2 years from William Optics

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

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