A Tri-Bahtinov mask operates under the same principle as the Bahtinov mask for focusing and adds the ability to collimate scopes with collimatable optics. The design is based on Cytan's idea, documented on his Github site here, and the sketch was made using Satoru Takagi's Mask Generator. The mask has a raised center for an easy grip and comes in three sections that snap fit together and can be taken apart for easier storage (C5 is one piece, 14" and larger are 6 sections).
If you don't see your scope listed below Buckeye will be happy to design a mask to meet your needs.
Hyperstar Note: The C6, C8, C9.25, C11 and C14 Tri-Bahtinov Masks accommodate both Hyperstar and native Fastar/secondary mirror configurations. The central hole is sized for the Hyperstar and the mask includes a snap fit bushing to decrease the diameter for the Fastar ring.
**For Hyperstar versions, the center hole accommodates the Hyperstar, and will not go around cameras that are wider than the Hyperstar body. In such cases the camera must be removed for installation and removal of the mask.
Printed in durable, temperature tolerant PETG filament.