Serrurier truss

The design was created in 1935 by engineer Mark U. Serrurier when he was working on the Mount Palomar 200 in (5.1 m) Hale Telescope.

[1] The design solves the problem of truss flexing by supporting the primary objective mirror and the secondary mirror by two sets of opposing trusses before and after the declination pivot.

The net result is all of the optical elements stay in collimation regardless of the orientation of the telescope.

Some Serrurier truss designs end the truss members with a short flexible rod creating a more ideal "parallel motion flexure" system, to allow maximum parallelism of optical elements under gravitational load.

Since truss members work primarily in tension and compression, there is no appreciable loss of stiffness due to the bending of the end flexures.

A Serrurier truss tube assembly on the Carl Zeiss Cassegrain telescope in Ostrowik near Warsaw.
Principle of operation of a Serrurier truss for a telescope compared to a simple truss. For clarity, only the top and bottom structural elements are shown. Red and green lines denote elements under tension and compression , respectively.