ToupTek OAG-L Large Format Off-Axis Guider

The ToupTek OAG-L is a large-format off-axis guider designed for use with ToupTek's DSO cooled cameras and full-frame or APS-C imaging sensors. By diverting a portion of the incoming light beam through a prism to the guide camera before it reaches the main imaging sensor, the OAG-L eliminates the differential flexure that plagues guide scope setups — ensuring rock-solid autoguiding accuracy across long exposures.

Product Overview

The OAG-L features a 10×10mm high-transmission prism mounted in a precision CNC-machined aluminium body. A removable spacer ring provides flexible back-focus adjustment to accommodate different camera and filter wheel configurations. The M54 front and rear threads connect directly to ToupTek ATR and SkyEye camera systems, with M48 adapters available for broader compatibility.

Who Is This Product Best For?

Astrophotographers using ToupTek cooled DSO cameras who want to eliminate differential flexure and improve guiding accuracy during long-exposure deep sky imaging. Particularly important on longer focal length telescopes where even small flexure errors become visible as trailing stars.

Why Choose This Product?

• Eliminates differential flexure — guide camera and imaging camera share the same optical path, so any mount error is measured and corrected precisely
• 10×10mm high-transmission prism — captures enough light for guide star detection without compromising main sensor illumination
• Removable spacer ring — adjust back-focus to suit different filter wheel and camera combinations
• M54 connection threads — designed for direct integration with ToupTek ATR and SkyEye camera systems
• 1.25" guide port — accepts any GPM, GPCMOS, or compatible guide camera directly
• Precision CNC aluminium construction — robust, lightweight, and dimensionally stable

Recommended Uses

• Long-exposure deep sky imaging requiring arc-second guiding accuracy
• Narrowband SHO and LRGB imaging sessions with ToupTek monochrome cooled cameras
• Any imaging setup where guide scope flexure causes star trailing or elongation

Compatibility and Accessory Notes

• Front/rear thread: M54×0.75 (M48 adapter available separately)
• Guide port: 1.25" — accepts ToupTek GPM462M, GPM174M, GPM290M/C, GPCMOS series, and other standard 1.25" guide cameras
• Compatible imaging cameras: ToupTek SkyEye62AC/AM, SkyEye24AC, ATR2600C/M, ATR533C/M, and other ToupTek DSO cooled cameras
• Compatible filter wheels: ToupTek AFW-M and AFW-L (confirm total back-focus budget before ordering)

Important Limitations

• Back-focus budget must be confirmed — adding an OAG consumes back-focus distance; verify your telescope and camera combination supports the required spacing
• Requires a guide camera — sold separately (ToupTek GPM or GPCMOS series recommended)
• Not for visual observing

Frequently Asked Questions

What is the difference between the OAG-L and OAG-X?
The OAG-L uses a 10×10mm prism and is the standard large-format model. The OAG-X uses a larger 14×10mm prism for a wider guide field. The OAG-X also has a slimmer body thickness. Choose the OAG-X when back-focus distance is critical or when you need a wider guide field for finding guide stars.

Which guide camera pairs best with the OAG-L?
The ToupTek GPM174M is ToupTek's recommended OAG guide camera — its large 1/1.2" sensor provides the widest field of view in the OAG port, maximising guide star detection. The GPM462M and GPM290M are also excellent choices.

Does the OAG-L work with non-ToupTek cameras?
Yes. The M54 thread is standard and M48 adapters are available. It can be used with any camera that has compatible threading and back-focus clearance.

Our Recommendation

The ToupTek OAG-L is essential equipment for serious long-exposure deep sky photographers. If you are using a ToupTek cooled camera and want reliable, arc-second guiding accuracy without flexure errors, the OAG-L is the correct solution. Pair it with the GPM174M for the best guide star coverage in the OAG port.