Is the curved mount as stable as the straight-vane mounts?
No, and there is no curved secondary design will match the mechanical strength that tensioned, straight, vanes can provide. However, ProtoStar curved mounts are more than rigid enough for the task, and are designed to satisfy both static and dynamic stability requirements as defined in the next paragraph. The minimum static flexure requirement is that collimation should not shift when the scope is slewed from a horizontal to vertical position. Dynamically, the secondary should not resonate excessively after a jolt to the tube. ProtoStar curved mounts are designed to dampen vibration well within one second.
