Starlight Xpress Active Optics Guiding System USB (48684)

The Starlight Xpress SX-AO-USB is an advanced active optics device designed to significantly reduce rapid guiding errors in CCD imaging. Many telescope mounts experience fast gear errors that are difficult to correct with standard motor speed adjustments. The SX-AO-USB solves this by using a high-speed, tip-tilt optical window to quickly adjust the image position, correcting errors almost instantly and without the settling delays of traditional guiding.

Unlike conventional tip-tilt mirrors, which require extra back focal distance and have sensitivity affected by the distance to the CCD, the SX-AO-USB uses a straight-through optical window. This design keeps the optical path short and provides a consistent, predictable image shift for each input step, regardless of the optical system or camera spacing.

The core of the system is a multi-coated, anti-reflection, plane-parallel optical window, 13 mm thick and 60 mm in diameter. It can tilt up to about ±3 degrees, giving a maximum image shift of approximately ±0.15 mm in both X and Y directions. For example, with an SX-825 camera, this equals about ±23 pixels of movement.

Integration and Ease of Use

The SX-AO-USB is designed to work seamlessly with Starlight Xpress Trius cameras, which feature a built-in USB2.0 hub. This allows you to control the SX-AO-USB, guide camera (such as the Lodestar X2), and Starlight Xpress USB filter wheel through a single connection, reducing cable clutter and preventing tangles or snags during imaging sessions. Both the guide camera and filter wheel are powered and controlled via USB, eliminating the need for extra power cables.

This system is ideal for astrophotographers seeking precise image stabilization, especially on mounts that are prone to rapid tracking errors. The SX-AO-USB helps ensure sharp, stable images by providing fast and reliable corrections directly in the optical path.

Key Features

• High-speed image tracking and stabilization using a tip-tilt optical window

• Fast correction speed of 5 milliseconds per increment

• Effectively compensates for rapid gear errors, stabilizing even challenging mounts

• Mount control output for correcting larger drive errors while maintaining active optics stabilization

• Consistent image shift, independent of optical system or camera back-focus

• Optional off-axis guider assembly for use with SXV guide cameras

• Compatible with STAR2000 guiding and many other camera types with suitable control software

• Clear 60 mm aperture, suitable for up to 35 mm full-frame sensors

• Short optical length: 74 mm with OAG, 44 mm without (add 6 mm with front end adapter)

• Minimal light loss (about 2%) due to multi-coated optics

• M48 filter threads for adding 48 mm filters (narrowband, IR-blocking, or pollution rejection) without affecting guide camera sensitivity

• USB controlled for easy integration

• Low power consumption: less than 600 mA at 12 V DC when moving, 50 mA at rest

• Compact and lightweight: 132 mm diameter x 32 mm length, less than 700 grams

Included Items

• SX-AO-USB unit

• AC mains adapter

• USB cable

• Guider cable

• Off-axis guider (optional for some versions)

• T-thread female adapter (telescope side)

• SCT-thread female adapter (telescope side)

• T-thread male adapter (camera side)

• M72-thread male adapter (camera side)

• CD-ROM with manual