



Pleiades 181
Elevate your stargazing and astrophotography experience with the newly launched Pleiades 181 by William Optics, a masterpiece exclusively designed for imaging with medium format cameras. This state-of-the-art telescope boasts a substantial 181mm diameter and a 998mm focal length, encapsulated in a sleek, robust design with a 3.7” R&P focuser for precise control.
Highlights
High-Performance Optics
The Pleiades 181 features a seven-element, temperature-compensated lens system, ensuring minimal thermal distortion and a Strehl ratio minimum of 0.96 for sharp, clear images across a greater than 55mm image circle.
Designed for Medium Format Cameras
Engineered specifically for medium format imaging, the Pleiades 181 is versatile in accommodating a variety of cameras. It comes equipped with three adapters for cameras with 48mm, 54mm, and 68mm threads, ensuring seamless compatibility and expansive celestial scene capture with unmatched clarity and color accuracy. This makes it an ideal choice for serious astrophotographers.
Unique Cosmos Steering Wheel
A pioneering addition, the Cosmos Steering Wheel allows for effortless handling, rotating, and precise positioning of the telescope, enhancing both comfort and functional ease during prolonged observation sessions.
Durable and Portable
Despite its large aperture, the Pleiades 181 remains relatively portable with a weight of 33.07 lbs (OTA only) and 41.23 lbs fully equipped with ring, dovetail, and saddle. The retracted and extended lengths are 1231mm and 1496mm respectively, with a dew shield diameter of φ230mm.
Why Choose Pleiades 181?
Designed with the specific needs of advanced astrophotographers in mind, the Pleiades 181 is not just a telescope, but a dedicated imaging gateway to exploring the cosmos with exceptional detail and depth. Whether you are capturing distant galaxies or the intricate patterns of nebulae, the Pleiades 181 brings the universe closer to you with unparalleled precision.
Explore the heavens with precision and elegance with the new Pleiades 181 from William Optics, where innovation meets the art of celestial imaging.
- Ships in one week
Accessory Add-ons
Guider










UniGuide 32mm f/3.75
- Lens Type
- Doublet Lens
- Focal Length
- 120 mm
- Diameter
- 32 mm
- Focal Ratio
- f/3.75
- Tube Length
- 147 mm
- Total Weight
- 0.23 kg / 0.51 lbs





Guiding Scope 50mm f/4.0
- Lens Type
- Doublet Lens
- Focal Length
- 200 mm
- Diameter
- 50 mm
- Focal Ratio
- f/4.0
- Tube Length
- 252 mm
- Total Weight
- 0.42 kg / 0.93 lbs










UniGuide 50mm f/4.0
- Lens Type
- Doublet Lens
- Focal Length
- 200 mm
- Diameter
- 50 mm
- Focal Ratio
- f/4.0
- Tube Length
- 252 mm
- Total Weight
- 0.5 kg / 1.1 lbs








GuideStar 61
- Lens Type
- Doublet APO Prime Lens
- Focal Length
- 360 mm
- Diameter
- 61 mm
- Focal Ratio
- f/5.9
- Image Circle
- 42 mm
- Focuser
- Threaded Focuser
- Adapter Included
- M54 → 2" Visual Back
- Optional Flattener
- FLAT 61A 1.0x FLAT 61R 0.8x
- Tube Length
- 340 mm
- Total Weight
- 1.44 kg / 3.17 lbs
Camera




ZWO ASI 533MC Pro
- Sensor
- Sony IMX533 CMOS ( color )
- Resolution
- 3008 × 3008
- Pixel Size
- 2.9μm
- Sensor Size
- 1″ ( 11.31 x 11.31mm )
- Max Frame Rate
- 20 fps
- Read Noise
- 1.0e
- Cooling Temp
- △35°C
- Quantum Efficiency
- 80%
- Full Well
- 50ke
- Exposure Range
- 32μs–2000s
- DDR3 Buffer
- 256 MB
- ADC
- 14 bit
- Flange Distance
- 17.5mm
- Camera Thread
- M42
- Adapter Included
- M48 → M42 Adapters ( 0 & 16.5mm ) M42 Extender ( 21mm ) M28.5 → M42 Adapter 1.25" Nosepiece → M42 Adapter
- Interface
- USB 2.0 Type-A USB 3.0 Type-B
- Cable Included
- USB 2.0 Type A↔B ( 0.5m ) x2 USB 3.0 Type A↔B ( 2m )
- Camera Weight
- 0.457 kg / 1 lbs
Camera Adapter



M48 T-mount for Pentax K
- Light-In Side
- M48 (female)
- Light-Out Side
- Pentax K Camera Mount
- Optical Length
- 9.3 mm



M48 T-mount for Canon EOS R Mirrorless
- Light-In Side
- M48 (female)
- Light-Out Side
- Canon EOS R Camera Mount
- Optical Length
- 34.4 mm



M48 T-mount for Nikon Z Mirrorless
- Light-In Side
- M48 (female)
- Light-Out Side
- Nikon Z Mirrorless Camera Mount
- Optical Length
- 38.4 mm






M48 T-mount for Canon EOS
- Light-In Side
- M48 (female)
- Light-Out Side
- Canon EOS Camera Mount
- Optical Length
- 10.6 mm



M48 T-mount for Fuji FX
- Light-In Side
- M48 (female)
- Light-Out Side
- Fuji FX Camera Mount
- Optical Length
- 37 mm



T-mount for Sony E
- Light-In Side
- M48 (female)
- Light-Out Side
- Sony E Camera Mount
- Optical Length
- 36.7 mm






M48 T-mount for Nikon F
- Light-In Side
- M48 (female)
- Light-Out Side
- Nikon F Camera Mount
- Optical Length
- 8.2 mm



M48 T-mount for Olympus Micro 4/3
- Light-In Side
- M48 (female)
- Light-Out Side
- Olympus Micro 4/3 Camera Mount
- Optical Length
- 35.6 mm


M48 → M42 Adapter
- Light-In Side
- M48 (female)
- Light-Out Side
- M42 (male)
- Optical Length
- 5.3 mm
EQ Mount









ZWO AM3 RedCat Limited Edition
ZWO x William Optics Co-branded Limited Edition
Traditional equatorial mounts often require heavy counterweights, making it challenging to balance the right ascension (RA) and declination (DEC) axes. They are cumbersome to transport and store, causing significant inconvenience for amateur astrophotographers during outdoor sessions. Additionally, some strain wave gear mounts have limited functionality, insufficient payload capacity, and lack stability during use. Addressing these issues, ZWO has developed the ASI Mount series, which eliminates the need for counterweights.
The AM3 weighs only 3.9 kg and supports payloads ranging from 8 kg to 13 kg. While portability is crucial, ZWO prioritizes stability to ensure a reliable user experience. The optimized internal structure incorporates harmonic drive reducers and timing belts, delivering precise control and an impressive 300:1 reduction ratio. The mount is versatile, functioning as either an equatorial or an alt-azimuth mount, and can be controlled via Wi-Fi, Bluetooth, or a handheld controller.
Key Features
Portability and Stability
The optimized internal structure, featuring harmonic drive reducers and timing belts, ensures precise control and stability, achieving a remarkable 300:1 reduction ratio.
Custom Strain Wave Gears
ZWO developed specialized strain wave gears tailored to astrophotography needs, offering extremely low periodic error and high torque. Each mount undergoes factory testing and comes with a unique PE curve to guarantee quality.
Lightweight Design
At just 3.9 kg, the AM3 strikes a balance between portability and stability, prioritizing dependable performance over extreme weight reduction.
8 kg to 13 kg Payload Capacity
Without Counterweights: Supports up to 8 kg.
With Counterweights: Supports up to 13 kg.
(Counterweights should be mounted on a bar no longer than 20 cm.)
Dual Modes: Equatorial and Alt-Azimuth
Equatorial Mode: Ideal for tracking and imaging celestial objects.
Alt-Azimuth Mode: Best suited for visual astronomy.
Easily switch modes using the ASI Mount App or the handheld controller.
Full 0°–90° Altitude Adjustment
Gear 1: Adjust the handle to set angles between 0° and 60°.
Gear 2: Loosen the hex screws to adjust the clamp for angles between 30° and 90°.
Wireless Control
Enjoy features like Tonight’s Target, GOTO, and Live Preview directly from your smartphone via Wi-Fi.
Joystick Hand Controller
Ergonomically designed for comfort and ease of use, the controller integrates with the Wi-Fi network for wireless operation. Firmware updates and installation can be managed effortlessly via a web interface.
Seamless ASIAIR Integration
The AM3 can be controlled via wired or wireless connection with ASIAIR, offering ZWO’s customers an optimized astrophotography experience.







ZWO AM5N RedCat Limited Edition
ZWO x William Optics Co-branded Limited Edition
Traditional equatorial mounts often require heavy counterweights, making them cumbersome to transport and balance. The AM5N addresses these challenges with a compact, counterweight-free design, offering enhanced portability and stability for amateur astrophotographers. Its optimized internal structure incorporates harmonic drive reducers and timing belts, delivering precise control and a 300:1 reduction ratio. The mount operates in both equatorial and alt-azimuth modes and can be controlled via Wi-Fi, Bluetooth, or a handheld controller.
Key Features
Enhanced Portability and Stability
Weighing only 5.5 kg, the AM5N supports payloads up to 15 kg without counterweights and up to 20 kg with counterweights, maintaining a balance between portability and performance.
Custom Harmonic Drive System
The AM5N features a custom harmonic drive system with a synchronous belt, ensuring high torque, zero backlash, and low periodic error of ±10 arcseconds.
Integrated Cable Management
Internal cable routing through the DEC saddle allows for seamless power and control connections, reducing cable clutter and the risk of snags during operation.
Dual Mount Modes
Switch effortlessly between equatorial and alt-azimuth modes using the ASI Mount App or the included hand controller. A status LED indicates the current mode: red for equatorial and green for alt-azimuth.
Wide Latitude Adjustment
The mount offers a full 0°–90° latitude adjustment range, accommodating various observing locations and setups.
Wireless and Wired Control Options
Control the AM5N via Wi-Fi, Bluetooth, or USB-C connections. The mount is compatible with the ASIAIR system and supports ASCOM and INDI protocols for versatile operation.
Power Failure Protection
An RA axis brake system engages automatically during power failures, safeguarding your equipment from potential damage.
Seamless ASIAIR Integration
The AM5N integrates seamlessly with ZWO's ASIAIR system, providing an optimized astrophotography experience through wired or wireless connections.




Mounting








Pair of Riser Blocks
- Length
- 80 mm
- Width
- 20 mm
- Height
- 20 mm
- Telescope
- FLT-132,156 UC-108,131
- Weight
- 195 g / 429.9 lbs
Tripod







Pier Mount 90
- Adapter
- 3/8" Thread ( for ZWO AM3/AM5 )
More EQ Mount types are optional - Weight
- approx. 7 kg
- Loading Capacity
- 90 kg / 198 lbs
- Height
- Stance: 89.3 cm Closed: 79.3 cm Foot Adjustable Height Range: 15 mm
- Material
- Aluminum Alloy
- Pillar Diameter
- 100 mm / 4"
![[Bundle] ZWO Mount Upgrade Kit](http://williamoptics.com/cdn/shop/files/ZWOMountUpgradeKit.jpg?v=1724140371&width=2400)
[Bundle] ZWO Mount Upgrade Kit
Make your ZWO AM3/5 tripod kit load-bearing and stable.


Tripod Extrapadding Backpack
This Tripod Extrapadding Backpack is specifically designed for astro EQ mounts tripod, offering added support and protection for your equipment.
- Thickness: 22mm
- Size: approximately 20 × 20 × 67 cm, with a measurement tolerance of ±3 cm.














Camouflage Tripod Pouch
Featuring durable Velcro straps for secure attachment, this pouch offers ample storage space to make your wildlife observation experience more convenient.
- Lens Type
- 7-Element Astrograph
- Lens Elements
- Super ED Glass x3
- Focal Length
- 998 mm
- Diameter
- 181 mm
- Focal Ratio
- f/5.5
- Image Circle
- 55 mm
- Focuser
- 4.1” R&P Focuser Compatible with EAF
- Focuser Travel
- 43 mm
- Adapter Included
- Tilt Adjuster Rotator M68 , M54 , M48 Camera Adapters
- Optional Flattener
- No Flattener Required
- T-Mount Support
- Canon EF, RF Nikon F, Z Sony E Pentax K MFT (M4/3) FUJI X
- Camera Format
- Medium Format Full Frame APS-C M4/3
- Dovetail Type
- Losmandy
- Tube Length
- 1231 mm - 1496 mm
- OTA Weight
- 15 kg / 33.07 lbs
- Total Weight
- 18.7 kg / 41.23 lbs
Choose options




Elevate your stargazing and astrophotography experience with the newly launched Pleiades 181 by William Optics, a masterpiece exclusively designed for imaging with medium format cameras. This state-of-the-art telescope boasts a substantial 181mm diameter and a 998mm focal length, encapsulated in a sleek, robust design with a 3.7” R&P focuser for precise control.
Highlights
High-Performance Optics
The Pleiades 181 features a seven-element, temperature-compensated lens system, ensuring minimal thermal distortion and a Strehl ratio minimum of 0.96 for sharp, clear images across a greater than 55mm image circle.
Designed for Medium Format Cameras
Engineered specifically for medium format imaging, the Pleiades 181 is versatile in accommodating a variety of cameras. It comes equipped with three adapters for cameras with 48mm, 54mm, and 68mm threads, ensuring seamless compatibility and expansive celestial scene capture with unmatched clarity and color accuracy. This makes it an ideal choice for serious astrophotographers.
Unique Cosmos Steering Wheel
A pioneering addition, the Cosmos Steering Wheel allows for effortless handling, rotating, and precise positioning of the telescope, enhancing both comfort and functional ease during prolonged observation sessions.
Durable and Portable
Despite its large aperture, the Pleiades 181 remains relatively portable with a weight of 33.07 lbs (OTA only) and 41.23 lbs fully equipped with ring, dovetail, and saddle. The retracted and extended lengths are 1231mm and 1496mm respectively, with a dew shield diameter of φ230mm.
Why Choose Pleiades 181?
Designed with the specific needs of advanced astrophotographers in mind, the Pleiades 181 is not just a telescope, but a dedicated imaging gateway to exploring the cosmos with exceptional detail and depth. Whether you are capturing distant galaxies or the intricate patterns of nebulae, the Pleiades 181 brings the universe closer to you with unparalleled precision.
Explore the heavens with precision and elegance with the new Pleiades 181 from William Optics, where innovation meets the art of celestial imaging.


