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, Gold or Space Grey.
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.
Specifications
| 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 | Integrated WIFD focuser |
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) |
Included items
- Gran Turismo 81 WIFD
- Lens cap with Bahtinov mask
- Finder saddle handle bar
- 210 mm Vixen-style dovetail bar
- Soft carry case
Instructions
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 |
For all orders exceeding a value of 100USD shipping is offered for free.
Returns will be accepted for up to 10 days of Customer’s receipt or tracking number on unworn items. You, as a Customer, are obliged to inform us via email before you return the item.
Otherwise, standard shipping charges apply. Check out our delivery Terms & Conditions for more details.
