Orion Optics UK Adaptor Plate for 225mm Diameter Tubes & Eris 2″ Rack & Pinion Focuser

This plate allows you to physically mount the high-precision Eris 2" rack and pinion focuser onto telescope tubes that have a 225mm outer diameter. It provides a secure, adjustable connection that is critical for both visual observation and astrophotography.

The eight tilt-adjustment screws let you precisely square the focuser drawtube to the telescope's optical axis. This is essential for astrophotography to ensure sharp, round stars across the entire field of view, eliminating elongated stars in the corners of your images that are caused by sensor tilt.

For the tilt adjustment to function correctly, you must first slightly loosen the main screws that fix the plate to the telescope tube itself. This provides the necessary clearance for the small tilt screws to make fine adjustments. Once your collimation is perfect, re-tighten the main fixing screws to lock it in place.

Yes. By slightly slackening the four screws that hold the Eris focuser to the plate, you can rotate the entire focuser body around its central axis. This is extremely useful for positioning your camera or eyepiece at the most comfortable or effective angle for your setup.

The plate adds 11mm of height at its central axis. You must account for this distance when measuring and calculating your total back focus requirements for flatteners, reducers, or other imaging accessories.

The plate features four mounting holes for the focuser, located on a 53mm radius and spaced 90 degrees apart from each other.