William Optics Gran Turismo 81mm f/5.9 FD Apo Triplet Refractor
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Product Details
The stunning new William Optics Gran Turismo 81APO is the new jewel of the apochromatic refractor world. From the pristine white finish on the CNC to the elegant darkred beauty which has more than just good looks... New GT81 features a 3-element objective using high-quality FPL-53 extra-low dispersion glass that reduces any secondary spectrum to an unbelievable degree.
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” DDG Focuser
- The Digital Display Gauge - DDG - allows you to take precise focusing readings down to two decimals precision instantly.
- Extra-smooth 360 deg. rotatable 2.5" Crayford focuser with 1:10 dual speed: a treat to use during astrophotography. No image shifting!
- Comes with two locking screws on angled positions for heavy load applications.
- Large aluminum knob with installed thermometer.
Patented Design
- Stainless steel reinforcement inserts on both sides and on the back to allow heavy loading without problems.
- DDG integration will make your focusing experience the best you ever experienced with a scope!
- Graduated scale for precise camera alignment.
Simply Beautiful Finish
- Pure William Optics quality fit and finish: powder-painted white CNC-machined aluminum tube, darkred finish, retractable dewshield, 360 deg. rotatable PowerLinear focuser, 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.
- Carry handle with V-shape night glowing illuminator.
- 90mm mounting rings are optional.
- 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!
| Aperture | 81mm |
| Focal Ratio | F/5.9 |
| Focal Length | 478mm |
| Objective Type | Triplet FPL-53 Air Spaced , Fully Multi-Coated, STM coatings |
| Resolving Power | 1.43 seconds of arc |
| Limiting Magnitude | 12.2 |
| Lens Shade | Retractable |
| DDG Focuser | 2" 360° Rotating Camera-angle Adjuster, 1:10 fine focus Focuser Travel Length 3.15" (80mm) 1.25" Adapter |
| 1.25" Adapter | Brass Compression Rings |
| Field Stops | 2 Baffles |
| Tube Diameter | 90mm |
| Tube Length | 340mm Fully Retracted 400mm Fully Extended |
| Tube Weight | 2.9 kg |
| Backpack | Carry-on rigid backpack with custom-fitted foam. |
| Backpack Dimensions (WxHxD) | 44cm x 30cm x 17cm (Water Resistant) |
| Case Weight | 1.8kg |
