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Mayall Mirror Lift Upgrade

Approximately 2 years ago, we determined that it was necessary to increase the capacity of the mirror lift in the Mayall telescope, in order to ensure that it could be used reliably in the future to handle the primary mirror and our Cassegrain-focus instruments. The modifications to the lift comprised replacing the 3 25-ton ball-screw actuators with 3 50-ton assemblies, and replacing the drive motor and mechanical linkages with 3 motors and a modern electronic control system. The first, preparatory phase of the work was completed in November; KPNO engineering and facilities staff are now roughly mid-way through the second, final phase of the work. The photos below indicate the scale of the effort. In order to minimize the science impact of the project, we needed to define a lengthy period in the schedule with no Cassegrain-focus instrument changes.

Figure 1
Figure 1 shows the removal of the drive plate with the old ball screws still in place

Figure 2 Figure 2 shows the three new ball screws and two actuators installed (compare the diameter of the ball screws in Figures 1 and 2).

Figure 3 Figure 3 shows the full assembly nearing completion.

Assembly is now virtually complete. We are now starting an extensive test period to confirm that the control system functions as designed. In particular, we need to fully exercise all plausible failure modes to ensure that personnel and equipment safety is assured.