Newton Reflector 3D printed primary mirror clips mask - part #3
Рет қаралды 1,927
@Bukuzoid 2 ай бұрын
Plastic has a very high coefficient of thermal expansion, in the cool of the night, the paws will put much more pressure on the mirror than you tightened them at home. This will cause deformation of the mirror and astigmatism, rubber gaskets will not help. It may not seem intuitive, but a very small pressure is enough for the deformation of the mirror to exceed 1/8 of the wavelength. In addition, the mirror is not perfect and any deformation is added to the already existing deviations. Another point is that plastic itself. PLA completely softens on +50C, Petg on +80C but can take slow non-elastic deformations on +50C too. During the transportation in the day's heat or exposing to sunlight under cover, they may weaken altogether and this thing will fall off and be lucky if it does not scratch the mirror before you find it is dangling inside. I would recommend make steel or carbon mask ring and fix it by same screws which are holding the mirror in it's frame.
@boaty1968 2 жыл бұрын
That seems better Pavle less flexible more stiffer 👍
@andyrawlins Жыл бұрын
is the gap between the mirror and the mask not a source of reflections/stray light?
@DeepSkyDad Жыл бұрын
Light hits the mask from the top and there are no gaps in the mask to reach the surface it the mirror. Unless I misunderstood the question.
@andyrawlins Жыл бұрын
@@DeepSkyDad OK thanks. I guess I was worried about stray light bouncing about underneath but I guess flocking will stop that. I'll just need to see if I have space between the mirror and tube for this.
@DeepSkyDad Жыл бұрын
@@andyrawlins we can customize the mask to some extent, if inner diameter of the tube is on the smaller side