Astronomy Specialist

GRAN TURISMO 81 IV F/5.9 APO TRIPLET

$2,499.00 AUD
SKU: WO-A-F81GTIVGD

William Optics

Apochromatic triplet

81 mm

f/5.9

478 mm

3.9 kg


Color: Gold
Style

 

The William Optics Gran Turismo 81 Version IV is a three element apochromatic refractor with 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.

The 2.5" 10:1 rack & pinion focuser is smooth, stable and reliable, providing no slippage over long imaging sessions. The newly designed rotator allows you to precisely adjust the angle of your camera.

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 also includes William Optics' innovative clear Bahtinov mask integrated into the lens cap.

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.

For best imaging results, it is recommended to pair the Gran Turismo 81 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.

GRAN TURISMO 81 F/5.9 APO TRIPLET & Flat6AIII spot diagram GRAN TURISMO 81 F/5.9 APO TRIPLET & Flat6AIII longitudinal aberration

 

Optical design

Apochromatic triplet

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

3.9 kg (including accessories)

Tube length

390 mm (fully retracted), 460 mm (fully extended)

Tube diameter

TBA

Dew shield diameter

TBA

SKU

WO-A-F81GTIVGD (Gold), WO-A-F81GTIVRD (Red)

 


 

  • Gran Turismo 81
  • 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

Customer Reviews

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A
Anxious in Perth
I'll get to use it one day...

So, I have had this scope for nearly a month and I'm still waiting for a chance to use it due to the constant cloud and the unusually high amount of rain here in WA this year.
In fact after posting my glee on receiving it on a local Facebook astro page my purchase has been subject to blame for the current state of the weather and much like it, is not letting up...

But one day I'll get that chance, until then it looks rather pretty sitting in the lounge on the HEQ5, catagorically the most expensive ornament I have ever had.
But pretty, oh so pretty.

GRAN TURISMO 81 F/5.9 APO TRIPLET.

GRAN TURISMO 81 IV F/5.9 APO TRIPLET

From $2,499.00 AUD

Color

Style

  • OTA Only
  • With 0.8x Reducer

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

3.9 kg

Length

Width

Height

View product