











MiniCat 51 WIFD
Designed for photography enthusiasts who love wide-angle views. Its standout feature is an ultra-bright f/3.5 aperture, allowing you to capture faint nebulae or comets in a very short time. (The f/3.5 aperture lets in twice as much light as an f/5 aperture.)
The MiniCat uses the latest Petzval design with 6 lens elements, including 2 Super ED and lanthanum lenses to perfectly control chromatic aberration. It’s currently the only high-quality, short focal length 178mm f/3.5 astrograph telescope available on the market.
The MiniCat holds three unique patents, ensuring easy and perfect focusing along with coaxial image quality to prevent drawtube tilt issues caused by optical misalignment.
Accessory Add-ons
Guider










UniGuide 32mm f/3.75
Enhance your astrophotography setup with the William Optics UniGuide 32mm f/3.75, a compact and versatile guide scope designed for precision and ease of use. This lightweight guide scope weighs only 240g and features a high-quality, fully multi-coated 32mm objective lens, ensuring bright, clear guiding stars.
The UniGuide 32mm offers a fast f/3.75 focal ratio and a 120mm focal length, ideal for accurately tracking celestial objects. It comes equipped with a slide-base Vixen/Synta-style rail for easy attachment directly to compatible William Optics telescopes, streamlining your setup and eliminating the need for conventional guidescope rings.
This guide scope is compatible with a variety of guide cameras, including popular models like the ZWO ASI120 Mini and Starlight Xpress Lodestars, thanks to its 1.25" adaptor and M42 thread. Available in four stylish colors—red, gold, space grey, and blue—the UniGuide 32mm not only performs superbly but also adds a touch of elegance to your astronomical equipment.
Whether you are a novice astrophotographer or a seasoned veteran, the William Optics UniGuide 32mm guide scope is an excellent addition to your astronomical toolkit, helping you achieve perfect tracking for flawless long-exposure images.
Camera




ZWO ASI 533MC Pro
The ZWO ASI533MC-Pro is a high-performance cooled color astronomy camera ideal for capturing deep-sky objects, as well as high-resolution images of the Moon, Sun, and planets. Its square-format sensor, advanced cooling system, and innovative design make it a versatile tool for astrophotographers of all levels.
Key Features
-
Square 1” Sony IMX533 Sensor
Equipped with a 9-megapixel back-illuminated CMOS sensor with 3008x3008 resolution and 3.76µm pixels, the camera is perfect for framing symmetric celestial objects like star clusters and nebulae. -
Enhanced Image Quality
The back-illuminated design improves sensitivity and reduces noise, with a high quantum efficiency (QE) of 80% and low read noise of just 1.0e. The sensor’s 50,000e full well capacity ensures bright stars remain sharp without saturation. -
Zero Amp Glow
Features advanced circuitry to completely eliminate amp glow, even during long exposures at high gain, resulting in cleaner, more accurate images. -
Efficient TEC Cooling and Anti-Dew Heater
A two-stage TEC cooling system reduces sensor temperature by up to 35°C below ambient, minimizing noise. The heat generated by the cooler also prevents dew formation on the camera window. -
Fast Data Transfer
Includes a 256MB DDR3 memory buffer for stable data transfer and reduced amp glow. The USB3.0 port supports fast data rates of 20 fps at full resolution. -
Dynamic Range and Low-Noise Performance
Offers a dynamic range of up to 14 stops, with optimal performance at a gain setting of 100. This makes it well-suited for electronically assisted astronomy (EAA) and traditional astrophotography.
Compact and User-Friendly Design
The ASI533MC-Pro is ideal for both deep-sky imaging and solar-system photography. Its compact size, powerful cooling, and versatile square sensor make it a perfect choice for astrophotographers seeking excellent performance and reliability in a streamlined package.
- 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
































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.



Counterweight Shaft
- Material
- Aluminum alloy
- Diameter
- 20 mm
- Shaft Length
- 210 mm

Tripod





Tripod Pouch
Featuring durable Velcro straps for secure attachment, this pouch offers ample storage space to make your stargazing experience more convenient.







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
- 6-Element Petzval
- Lens Elements
- Super ED Glass x2
- Focal Length
- 178 mm
- Diameter
- 51 mm
- Focal Ratio
- f/3.5
- Image Circle
- 43.2 mm
- Focuser
- WIFD R&P Focuser Compatible with EAF
- Focuser Travel
- 0-28 mm (Ruler to 40)
- Back Spacing
- 58-30mm
- Adapter Included
- Tilt Adjuster Rotator M54 → M48 Adapter
- 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
- Full Frame (Compatible) APS-C (Recommended) M4/3
- Dovetail Type
- Vixen ↔︎ Arca-Swiss
- Tube Length
- 210 mm
- OTA Weight
- 1.67 kg / 3.68 lbs
- Total Weight
- 2.29 kg / 5.05 lbs
Choose options












What's in the box

Main Tube

Bahtinov Cap

M48 Camera Adapter

Dual-side Plate

Mounting Ring & Handle bar

Soft Carry Case

Allen Key Set


Agile & highly efficient
Designed for photography enthusiasts who love wide-angle views. Its standout feature is an ultra-bright f/3.5 aperture, allowing you to capture faint nebulae or comets in a very short time.


UltraFast Petzval
The innovative 6-element Petzval design boosts traditional Cat telescopes' efficiency with a cutting-edge optical system.
Extra-low Dispersion (ED) glasses
Contains 2 Super ED glasses and lanthanum lenses with advanced fully multi-coated, delivering sharp, vibrant images with true-to-life colors, significantly reducing chromatic aberration.


Needs NO Flattener

ultra-bright
f/3.5 Aperture
2x
faster than
RedCat 51 (f/4.9)
FOV Performance
Toggle between tabs to see the difference in field of view.

Image Circle: 43.2 mm
Focal Length: 178 mm

Image Circle: 48 mm
Focal Length: 250 mm

Compatible with Electronic Motorized Devices
Hassle Free Installation
( No Mounting Bracket Kit required )
Leading the market
Wo patented design
The MiniCat holds three unique patents, ensuring easy and perfect focusing along with precise coaxial image quality, preventing draw tube tilt issues caused by optical misalignment.
:
Internal Focuser


Integrated Bahtinov mask
CAT Handle Bar
Crafts for enhanced portability and versatility.
Mounting Ring
Designed for seamless functionality without compromising on stability. Engineered with wide surface contacts, this innovative ring ensures a secure fit while enabling fast, easy detachment.

Dual side Dovetail Plate
The lightweight dovetail plate is designed with both Vixen-style and Arca-Swiss types, offering enhanced compatibility with various mounts and mounting rings.


comprehensive configuration
Precision Imaging Adjustment

Tilt Adjuster
The built-in tilt adjuster makes it easy to correct camera sensor tilt issues.

Camera Angle Rotator
Correctable Corner Imperfections
Due to the nature of MiniCat’s fast aperture optical design, edge stars may not be as round as with other RedCats. However, our tests show it still outperforms conventional lenses. With aberration correction software like BXT, peripheral distortions can be perfectly corrected on APS-C sensors, while Full Frame may need some fine-tuning for even better results.
:
▼ APS-C ( Recommended )

Before Process

After Process
Gallery
Swipe left and right to view the Original & After processed image.

Original

After Process

▲ M8+M20 (APS-C)
MiniCat 51 + ZWO ASI 2600MC Duo
Courtesy of Dear Bear
- Stacked ( Original & After Process )
- Original Single Shot Corner Grid

Original

After Process

▲ M24 (APS-C)
MiniCat 51 + ZWO ASI 2600MC Duo
Courtesy of Dear Bear
- Stacked ( Original & After Process )
- Original Single Shot Corner Grid









