William Optics ZenithStar 81mm f/6.9 Doublet Apo Refractor with Soft Case & Flat6AIII Fi...
Availability: Discontinued by the vendor. No longer available.
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- Premium 81mm apochromatic refractor for astronomical imaging and visual observation
- Apochromatic f/6.9 doublet objective with FPL-53 glass
- Large image circle for imaging with APS-C and full-frame sensors when used with the included field flattener
- Compact form factor and light weight ideal for transport and travel
All New Super ZenithStar 81 F6.9 imaging APO - Innovative Bahtinov Mask Cover (Patented) and soft carry case included!
ZenithStar 81 Doublet Apochromatic Refractor
The William Optics ZenithStar 81 is an extremely well crafted and versatile refractor, an ideal instrument for deep sky imaging with DSLRs or dedicated astronomy cameras with APS-C and full-frame sensors. It’s also a great tool for visual observation of a wide range of celestial objects from the moon and planets to nebulae and star clusters and brighter galaxies, as well as for solar observation with a safe solar filter.
The ZS81 features an 81mm f/6.9 FPL 53 air-spaced doublet apochromatic objective lens in a CNC machined ultra-high precision cell. These premium optics provide razor-sharp images and excellent color rendition. When paired with a 0.8x William Optics field flattener and focal reducer (sold separately), the scope works at a fast f/5.5 with a flat field across the entire 43.3mm diagonal of a full-frame sensor.
Premium Build Quality and Compact Form Factor
Like all telescopes from William Optics, the ZenithStar 81 incorporates rock-solid mechanics and built quality. The scope includes high-quality mounting rings to safely and securely hold the telescope to the mount. The rings are anodized to match the color of the handle, dovetail, and focuser, giving the scope an attractive, premium appearance.
With a focal length of 559mm, this f/6.9 telescope has a retracted length of just 456mm (18”), compact enough to qualify as carry-on luggage with many airlines. The tube weighs just 3.50kg (7.8 lbs) including tube rings and dovetail plate.
Heavy-Duty Focuser, Rings, Soft Case and Accessories
The William Optics ZS 81 features a patented objective lens cover that doubles as clear Bahtinov focusing mask. This makes it a snap to achieve sharp focus when setting up for astrophotography.
The ZS 81 also features a heavy duty 10:1 dual-speed 2.5” rack and pinion focuser with tension screws to securely hold a bigger camera and accessories without slipping or image shift, even during longer exposures. The focuser also includes two additional screws to mount an optional red-dot finder.
A convenient CNC-machined carrying handle mounts on top of the rings and doubles as a holder for a guide scope (sold separately). On the bottom of the rings is a 210mm long reversible dovetail with a Vixen rail on one side and an Arca Swiss mount on the other for mounting the scope to a camera tripod for grab-and-go terrestrial and astronomical observation.
A soft carry case is now also included with this telescope.
Specifications:
- Focal length: 559mm
- Diameter: 81mm
- Aperture: f/6.9
- Camera Format: APS-C, Full Frame
- Focuser: 2.5" R&P
- Image Circle: Full Frame
- Flattener: Flat6AIII
- Tube Length (Fully Retracted): 460mm
- Tube Length (Fully Extended): 560mm
- Tube Weight: 3.53kg
- Interchangeable T-Mounts (sold separately): Canon EF, Nikon F, Sony E, Pentax, Micro Four Thirds, Fuji FX
All William Optics telescopes come with a 2-year no-fuss warranty from William Optics.
Flattener Description:
2019 All New Adjustable Flat6AIII (T-mount not included)
This very elegant 2" reducer/field flattener has been designed to optimize the flat-field imaging performance of William Optics F/6 to F7.5 ratio refactors. WO Flat 6AIII will provide good illumination and flat field across 97% of full frame sized sensors.
Full frame size
- Designed with nearly Full frame chip-size DSLR cameras in mind.
- FMC triplet APO design.
- Produced entirely with the best Ohara optical glasses.
Amazing
- Reducing factor 0.8X.
- Adjustable design, for perfect back focus it can be used with other models of refractor
- 48mm filter ready
Superb Finish
- William Optics polished anodized finish.
- All internal surfaces threaded and blackened to prevent reflections.
Easy to Use
- Will accept any standard 48mm wide T-ring for your camera. Not compatible with smaller 42mm T rings.
Suitable for
- Newer GT71, GT81, Z81, Z103 scopes that have a female M63 thread. Please check your telescope before ordering.
Adjustment Distance
- GT71: 9.1mm
- GT81: 7.1mm
- Z81: 5.2mm
- Z103: 2.5mm
| Manufacturer | William Optics |
|---|---|
| Product Banner Type | discontinued |
| Free Shipping Graphic | Free US Shipping |
| Hide Found a better Shipped Price on Frontend? | No |
- ZenithStar 81
- Flat6AIII reducer/field flattener
- Patented Bahtinov mask cover
- Dual-speed 2.5” focuser
- Mounting rings
- Handle
- Soft carry case
- Dual dovetail plate
- Premium 81mm apochromatic refractor for astronomical imaging and visual observation
- Apochromatic f/6.9 doublet objective with FPL-53 glass
- Large image circle for imaging with APS-C and full-frame sensors when used with the included field flattener
- Compact form factor and light weight ideal for transport and travel
All New Super ZenithStar 81 F6.9 imaging APO - Innovative Bahtinov Mask Cover (Patented) and soft carry case included!
ZenithStar 81 Doublet Apochromatic Refractor
The William Optics ZenithStar 81 is an extremely well crafted and versatile refractor, an ideal instrument for deep sky imaging with DSLRs or dedicated astronomy cameras with APS-C and full-frame sensors. It’s also a great tool for visual observation of a wide range of celestial objects from the moon and planets to nebulae and star clusters and brighter galaxies, as well as for solar observation with a safe solar filter.
The ZS81 features an 81mm f/6.9 FPL 53 air-spaced doublet apochromatic objective lens in a CNC machined ultra-high precision cell. These premium optics provide razor-sharp images and excellent color rendition. When paired with a 0.8x William Optics field flattener and focal reducer (sold separately), the scope works at a fast f/5.5 with a flat field across the entire 43.3mm diagonal of a full-frame sensor.
Premium Build Quality and Compact Form Factor
Like all telescopes from William Optics, the ZenithStar 81 incorporates rock-solid mechanics and built quality. The scope includes high-quality mounting rings to safely and securely hold the telescope to the mount. The rings are anodized to match the color of the handle, dovetail, and focuser, giving the scope an attractive, premium appearance.
With a focal length of 559mm, this f/6.9 telescope has a retracted length of just 456mm (18”), compact enough to qualify as carry-on luggage with many airlines. The tube weighs just 3.50kg (7.8 lbs) including tube rings and dovetail plate.
Heavy-Duty Focuser, Rings, Soft Case and Accessories
The William Optics ZS 81 features a patented objective lens cover that doubles as clear Bahtinov focusing mask. This makes it a snap to achieve sharp focus when setting up for astrophotography.
The ZS 81 also features a heavy duty 10:1 dual-speed 2.5” rack and pinion focuser with tension screws to securely hold a bigger camera and accessories without slipping or image shift, even during longer exposures. The focuser also includes two additional screws to mount an optional red-dot finder.
A convenient CNC-machined carrying handle mounts on top of the rings and doubles as a holder for a guide scope (sold separately). On the bottom of the rings is a 210mm long reversible dovetail with a Vixen rail on one side and an Arca Swiss mount on the other for mounting the scope to a camera tripod for grab-and-go terrestrial and astronomical observation.
A soft carry case is now also included with this telescope.
Specifications:
- Focal length: 559mm
- Diameter: 81mm
- Aperture: f/6.9
- Camera Format: APS-C, Full Frame
- Focuser: 2.5" R&P
- Image Circle: Full Frame
- Flattener: Flat6AIII
- Tube Length (Fully Retracted): 460mm
- Tube Length (Fully Extended): 560mm
- Tube Weight: 3.53kg
- Interchangeable T-Mounts (sold separately): Canon EF, Nikon F, Sony E, Pentax, Micro Four Thirds, Fuji FX
All William Optics telescopes come with a 2-year no-fuss warranty from William Optics.
Flattener Description:
2019 All New Adjustable Flat6AIII (T-mount not included)
This very elegant 2" reducer/field flattener has been designed to optimize the flat-field imaging performance of William Optics F/6 to F7.5 ratio refactors. WO Flat 6AIII will provide good illumination and flat field across 97% of full frame sized sensors.
Full frame size
- Designed with nearly Full frame chip-size DSLR cameras in mind.
- FMC triplet APO design.
- Produced entirely with the best Ohara optical glasses.
Amazing
- Reducing factor 0.8X.
- Adjustable design, for perfect back focus it can be used with other models of refractor
- 48mm filter ready
Superb Finish
- William Optics polished anodized finish.
- All internal surfaces threaded and blackened to prevent reflections.
Easy to Use
- Will accept any standard 48mm wide T-ring for your camera. Not compatible with smaller 42mm T rings.
Suitable for
- Newer GT71, GT81, Z81, Z103 scopes that have a female M63 thread. Please check your telescope before ordering.
Adjustment Distance
- GT71: 9.1mm
- GT81: 7.1mm
- Z81: 5.2mm
- Z103: 2.5mm
| Manufacturer | William Optics |
|---|---|
| Product Banner Type | discontinued |
| Free Shipping Graphic | Free US Shipping |
| Hide Found a better Shipped Price on Frontend? | No |
- ZenithStar 81
- Flat6AIII reducer/field flattener
- Patented Bahtinov mask cover
- Dual-speed 2.5” focuser
- Mounting rings
- Handle
- Soft carry case
- Dual dovetail plate