These single truss designs are used for their rigidity and do perform the function of keeping the optical elements parallel, but since they lack the opposing truss that keeps optics on the same optical axis they are not technically "Serrurier trusses". Certain designs used by amateur telescope makers, specifically truss tube Dobsonians that use a single truss, are sometimes called "Serrurier truss" designs. The truss tubes connect the mirror box to the upper cage. [citation needed]. 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. The other four tubes connect to the top of … Our standard design also includes a Kevlar lower-edge sling support. The design of the telescope calls for a truss frame with 8 tubes. The trusses are designed to have an equal amount of flexure, which allows the optics to stay on a common optical axis. The carbon-fibre tubes are stiff, light and especially thermally stable - another reason why there is no focus drift. When flexing, the "top" truss resists tension and the "bottom" truss resists compression. Other examples of Serrurier truss designs: Serrurier truss used on the Mayall Telescope. This has the effect of keeping the optical elements parallel to each other. Animation of a Serrurier truss under load, Animation of a Serrurier truss under load, slanted view, Encyclopedia of Astronomy and Physics, "Reflecting Telescopes", Paul Murdin and Patrick Moore, astro.caltech.edu - Reflecting Telescopes, https://en.wikipedia.org/w/index.php?title=Serrurier_truss&oldid=974046939, Articles with unsourced statements from January 2013, Creative Commons Attribution-ShareAlike License. A Serrurier truss is used in telescope tube assembly construction. Since truss members work primarily in tension and compression, there is no appreciable loss of stiffness due to the bending of the end flexures. When flexin… "The Legacy of the 200-inch". A Serrurier truss is used in telescope tube assembly construction. The stiffness of the frame is the combination of the following: Truss Frame of the 110 cm Cruxis Telescope, round tube diameter 38 mm / thickness 1.5 mm => 0.464 kg/m, round tube diameter 30 mm / thickness 2 mm => 0.475 kg/m, square tube side 30 mm / thickness 1.5 mm => 0.462 kg/m, Design weight: 13 kg (upper cage) + 7 kg (half total tube weight) = 20 kg, Average free length of the tubes: L = 3350 mm, Base separation of the tubes: C = 1100 mm, Cross section of the 30 x 1.5 mm square tube: A = 171 mm, Section modulus of the 30 x 1.5 mm square tube: I = 23,200 mm, Elasticity modulus of aluminum: E = 70,000 N/mm. The net result is all of the optical elements stay in collimation regardless of the orientation of the telescope. Four tubes are about 3700 mm (12 ft) long and connect to the mirror box at the level of the primary mirror. The cell pivots from the lower "rung" and is held in place by two 5/16" bolts with acorn nuts on the face-side of the mirrorbox. "Flexure of a Serrurier Truss", This page was last edited on 20 August 2020, at 19:49. Diffrient, Roy. Our standard design allows the mirror cell to "tailgate" or "tip out" for easy installation and removal of the primary mirror. Learner, Richard. The trusses are designed to have an equal amount of flexure, which allows the optics to stay on a common optical axis. 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. [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 tension-compression truss stiffness of the 2 vertical triangles: The bending stiffness of the 8 tubes anchored at the mirror box and the upper cage. Most professional telescopes use a truss-tube design and this telescope enjoys exactly the same advantages. Natural ventilation is better with a truss-tube design and prevents the system from developing its own microclimate. 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. 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. Serrurier truss designs: Serrurier truss used on the Mayall telescope ventilation is better with a truss-tube and. Reason why there is no focus drift the optics to stay on a common optical axis on August. 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