Astronomy Specialist

GRAN TURISMO 81 WIFD F/5.9 APO TRIPLET

$3,599.00 AUD
SKU: WO-T-GT-81RD-WIFD

William Optics

Apochromatic triplet

81 mm

f/5.9

478 mm

3.3 kg


 

The William Optics Gran Turismo 81 WIFD is a game-changing new three element apochromatic refractor featuring a patented internal focus design. The WIFD series has been designed from the ground up to support the latest large and heavy high-resolution cooled cameras and accessories.

The focuser movement is integrated inside the main OTA, so no external focuser drawtube is needed. This will reduce tilt caused by focuser sag and mechanical flex and lessen vignetting.

 

 

The focuser utilizes a zero image shift rack & pinion mechanism for precise adjustability of critical focus, with an external graduated display showing focus position. The lens cell is protected from the elements and is designed to not come out of alignment. The focuser is fully compatible with the ZWO EAF without the need for optional accessories.

Like the Gran Turismo 81 IV, the WIFD has a focal ratio of f/5.9 and a focal length of 478mm. Utilizing FPL-53 synthetic fluorite glass, this telescope provides excellent aberration correction. As the imaging train is connected to the rear of the solid tube, no flex will be introduced when heavy accessories are connected.

The CNC-machined and anodized handle bar with finder-style saddle is perfect for attaching a guide scope or other accessories. The Gran Turismo 81 WIFD also includes William Optics' innovative clear Bahtinov mask integrated into the lens cap. The included field rotator features exceptionally smooth operation with degree markings and a locking thumbscrew to prevent accidental movement.

William Optics uses high quality steel lens cells for their Gran Turismo and FLT triplet refractors. This is perfect for temperature compensation and will prevent pinched optics in cold weather conditions.

Available in Red.

For best imaging results, it is recommended to pair the Gran Turismo 81 WIFD with its matching Flat6AIII 0.8x field flattener.

Note: As the Flat6AIII an adjustable flattener, you must adjust the distance for your specific telescope. See the Instructions tab above.



 

Optical design

Apochromatic triplet with integrated focuser

Objective diameter

81 mm

Focal length

478 mm

Focal ratio

f/5.9

Image circle

44.4 mm (with Flat6AIII field flattener)

Compatible flattener

William Optics Flat6AIII

Mount attachment

210 mm Vixen-style/Arca-Swiss dovetail bar

Focuser

Rack & pinion dual speed (10:1) 2.5" diameter

Camera connection

M63 x 1, 2"

Backfocus

62.1 mm (with flattener/reducer)

Tube weight

3.3 kg (4.5 including accessories)

Tube length

420 mm (fully retracted), 500 mm (fully extended)

Tube diameter

TBA

Dew shield diameter

TBA

SKU

WO-A-F81GTIVRD (Red)

 


 

  • Gran Turismo 81 WIFD
  • Lens cap with Bahtinov mask
  • Finder saddle handle bar
  • 210 mm Vixen-style dovetail bar
  • Soft carry case

 

Note: Once you have unscrewed the rear adapter to the appropriate value in the table below, the remaining backfocus distance to make up will be 55mm from the rear M48 thread.  

Distance adjustment needed for correct backfocus

GT71
9.1 mm
GT81
7.1 mm
Z81
5.2 mm
Z103
2.5 mm


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GRAN TURISMO 81 WIFD F/5.9 APO TRIPLET.

GRAN TURISMO 81 WIFD F/5.9 APO TRIPLET

$3,599.00 AUD

Optical design

Apochromatic triplet

Image circle

Focal ratio

f/5.9

Aperture

81 mm

Focal length

478 mm

Optical thickness

Threads

Cooled

Colour or Mono

Pixel size

Sensor dimensions

Resolution

Sensor diagonal

Quantum efficiency

Read noise

Fullwell capacity

Bit depth

FPS

Camera backfocus

Filter size

Filter size

Bandpass (FWHM)

Bandpass (FWHM)

Glass thickness

Mount type

Payload capacity

Latitude range

Dovetail saddle

Slew speed

Encoders

Periodic error correction

Counterweight shaft

Azimuth adjustment range

Internal diameter

Illuminated diameter

Compatible telescope external diameter

Weight

3.3 kg

Length

Width

Height

View product