Thursday, August 5, 2010

Almost, but not quite!

After undergoing the necessary mods, the stiffening ring for the on-telescope-test (OTT) was installed beneath the floor of the non-rotating structure (NRS).

Monday's Faro measurements made on the tracker led to a set of spacers of specific thicknesses that will square up the SAC's aluminium collar against the NRS.

The spacers were bonded to the collar - being sure to place them in the right order!

The collar could then be taken up to the tracker platform & installed...

The image below can be compared with a similar one in the Monday (2 August) post to see all the new hardware in place: the ring for the OTT (the black wall inside the old aluminium interface ring), the aluminium collar (black ring outside the old interface ring) & the auto-collimator assembly (instrument at the 12 o'clock position outside the collar).

At this stage, we believed it was time to lift the SAC & so it was wheeled out of the clean room & attached to the dome crane.  However, a likely source of mechanical interference between the SAC & the OTT gear was identified so the lift was halted & the problem confirmed.  Modifications will be made & the lift ought to proceed next week...

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