Quote:
Originally Posted by Mark Suchting
No, the triangles are correct for 27 point. The 9 triangles would *normally* be mounted on the apexes of three large triangles which would in turn connect to three collimation bolts in a back plate. By ommitting this 3 triangle layer in the 16" Lightbridge, any micro twisting of the back plate under load at different altitude is transmitted direct to the mirror , nor is mirror sag compensated for if the backplate yields to the changing loads. In a correct 27 point floatation system, a deformation of the rear plate will only cause a slight mis -collimation tilt of a well floated thin mirror, but no deformation of it.
This is a clear example of the compromise that must be expected in such a package at that price. 12" is probably the cut off point at which you can 'get away ' with a lot more , regards mirror material and mounting technology, particularly as mirror flexure goes up by the cube of the aperture, given constant thickness ratio. So just urging some realism in your expectations as always.  |
Cool, missed by that much!