Baader Hyperion Extension Ring - SP54/SP54 11mm Long

This ring's primary function is to add exactly 11mm of length to an optical train. This is crucial for astrophotography when you need to achieve the precise back focus distance specified by an optical corrector, such as a field flattener or coma corrector.

You use this 11mm ring to fill a gap in your imaging train. First, you add up the optical path length of your camera, T-ring, and any other adapters. If the total is, for example, 44mm, you would add this 11mm extension ring to reach the required 55mm distance for optimal coma correction.

The SP54 thread is the native system thread on Baader Hyperion eyepieces (revealed when the barrels are removed) and is used across their adapter system. This 11mm ring is designed to connect directly to these eyepieces for projection imaging or to other Baader SP54 accessories and T-rings.

Yes, the Baader system is modular, and you can stack multiple SP54 rings to create custom lengths. However, for maximum rigidity and to avoid potential tilt, it is always recommended to use a single extension ring that is closest to your required length rather than stacking many smaller ones.

Yes, it will thread onto any astronomy accessory that has a matching male or female SP54 thread. While designed for the Baader system, the standardized threading allows for cross-brand compatibility where SP54 is used.

This ring is almost exclusively for astrophotography. Its purpose is to precisely set sensor distance, which is not a concern for standard visual observing. An exception would be for eyepiece projection photography, where this ring would be used to set the distance between a Hyperion eyepiece and a camera sensor.