M.Kesteven, M.Calabretta, G.Graves, B.Parsons
The inner 44m of the parkes reflector was adjusted during the week of 10-13 december. The main ambition was to raise, by about 3mm, the panels near the lift leg, to correct for the additional load imposed by the new focus cabin.
The measurements and analysis which lead to the adjustment campaign are detailed in the surface-change document .
The adjustments were guided by 12 GHz holography surveys - see the pre-adjustment image, and post-adjustment image .
The holography analysis indicates that the inner section's rms has dropped from 0.83mm to 0.6mm, which implies an improvement in gain of 0.4 dB (10%) at 12 GHz. This is doubtless optimistic, but it does suggest that much of the reported 22 GHz efficiency loss may have been recouped.
The outer mesh area which also needs attention will be attacked in early january.