The only thing that won't look concenctric will be the image of the secondary in the primary mirror. Everything else will be nicely concenctric - the secondary will look concenctric as the further part of that secondary will look smaller than the near side angle wise, the image of the primary will be concenctric on the secondary surface as you have put the secondary so that it reflects the center of the primary light cone. The tube edge should look concenctric to the primary as this is the aperture of the incoming beam at that point and should be by definition concentric in the primary.
The secondary's shadow will not be concentric as it is offset so you will have a little offset of that image.

• Collimation - jwrking - March 2, 2004 - 09:06 UTC