The ZWO OAG-L Off-Axis Guider is a high-performance guiding solution designed for demanding astrophotography setups, particularly those using full-frame cameras. By guiding through the same optical path as the main imaging camera, it delivers precise star tracking while reducing overall system weight and eliminating differential flexure.

Why Choose the ZWO OAG-L?

• Exceptional Compatibility: Designed to work seamlessly with ZWO ASI cameras and full-frame sensors.
• Large Guiding Prism: Ensures reliable guiding even on faint stars.
• Ultra-Slim Profile: Only 17.5mm thick, preserving precious back focus.
• Easy Setup: Supplied with adapters and adjustment hardware for straightforward installation.

Optimised for Full-Frame Astrophotography

The ZWO OAG-L is engineered to complement full-frame imaging cameras, offering a wide, well-illuminated guiding field with minimal vignetting. Its robust prism design delivers ample light to the guide camera, even during long exposures of nebulae, galaxies, and star clusters.

Key Features

• Slim Design: 17.5mm thickness
• Large Prism: Designed for reliable guiding
• Wide Compatibility: Suitable for ZWO ASI cameras and standard threaded imaging trains
• Durable Construction: Lightweight yet rigid housing
• Adjustable Prism & Focus: For accurate alignment

What’s in the Box?

• ZWO OAG-L Off-Axis Guider
• 1.25" and M42 adapters
• M48–M54 adapter ring
• Allen wrench and mounting screws
• User manual

Specifications

Why Off-Axis Guiding Matters

Unlike traditional guide scopes, off-axis guiding removes flexure by using the same optical path as the imaging camera. The ZWO OAG-L provides a compact, accurate, and efficient guiding solution for advanced imaging systems.

Features

1. Ultra-slim 17.5mm body
2. Large 12 × 12 mm prism
3. No separate guide scope required
4. Includes 5mm M48 sensor tilt plate

Operating Notes

1. Compatible with ASI Mini guide cameras such as ASI174MM Mini, ASI290MM Mini, and ASI120MM Mini.
2. Not recommended for optical systems with a clear aperture smaller than M48.
3. Best used with 2" or 7×36mm EFWs and APS-C or full-frame cameras.
4. OAG-L removes inner threads, allowing direct screw-based connections.
5. Sensor tilt plate usage depends on telescope-side thread type.

Sensor tilt plate removal examples:

Mechanical Diagram

Connection Examples

Please Note

Ensure the prism does not intrude into the imaging sensor’s field of view when installing the OAG-L.

Use the guiding screw to match the optical distance between the prism and both the imaging and guide cameras. Daytime adjustment is strongly recommended, as fine tuning at night can be difficult.