The first step in detemining the feasibility of various support concepts was to look at mounting the mirror with its axis held vertically on simple central mount. We determined how much surface error resulted from gravity. Three cases were examined at:
These models yielded the raw surface deflections shown in the figure below:
Next the best fit parabola was removed from the surface errors to determine how much of the error could be removed in the telescope system simple by alignment and focus, these results are shown in the next figure:
It is clear that the residue error is still far greated than is required even with the curved back mirror However, the shape of the mirror back has a profound effect on the nature of the mirror deflection under gravity. We will be examining off-loading systems to further reduce the gravity induced errors.
