NEW: With the addition of Baader's new Finetuning Rings, each Hyperion eyepiece can now function as four eyepieces! Available in 14mm and 28mm lengths. The finetuning rings are 2" OD and threaded M48 (filter thread) on each end, so they can be installed in-between the Hyperion's removable front negative element and main body. The added spacing decreases the focal lengths (increases magnification), according to the table below. Finetuning rings are made to match the Hyperion finish, and are fully internally sharp v-threaded and blackened to eliminate stray light reflections from the internal surfaces.
Also, another novel way to change eyepiece focal length is to use a Baader 2" Filter in-between the Hyperion negative element and main body, just like a small finetuning ring. The 8.5mm thickness of the filter cell will have a similar (milder) effect in reducing the Hyperion's focal length. This also allows use of 2" filters with Hyperions, something that is not possible with any other 1¼" Eyepiece.
Please Note: Removal and installation of the front negative element should be done in a clean environment to prevent dust or other contamination from depositing on the internal elements (which are very difficult to clean). Also, please note that the 24mm Hyperion is not able to make use of the Finetuning Rings, due to its different optical design.