GRAN TURISMO 81 IV F/5.9 APO TRIPLET
William Optics
Apochromatic triplet
81 mm
f/5.9
478 mm
3.9 kg
GRAN TURISMO 81 IV F/5.9 APO TRIPLET - Red / OTA Only is backordered and will ship as soon as it is back in stock.
Astronomy Specialist
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.
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) |
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 |
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.
Color
Style
Optical design
Image circle
Focal ratio
Aperture
Focal length
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
Length
Width
Height