SUMMARY
The central bearing load was adjusted during the day. The gamble of aborting the scheduled afternoon inclinometry and evening pointing failed and the process had to be restarted at 21:30. CW inclinometry was followed, starting 01:30 on the 7th, by SCUBA pointing. New track and telescope models were installed and behaved satisfactorily thereafter.

   Datasets     HST start      mean leg temperatures   Humidity
                               start   middle   end       %
 ( inc000526 cw   17:30         1.9     1.9     1.7      80 )
   inc000606 cw   21:30         4.0     4.0     4.0      20

The difference between these clockwise models is shown below :

• There are clear, track-segment related, differences : not unexpectedly due to the change in load.
• The formal differences in the (F1,F2,F3) terms are described by the rms scatters of (1.2",0.4",0.6") cf (0.56", 0.29", 0.45") previously.

• The new track model was installed at 01:30 HST on 20000607.

• The symmetry remains reasonably good : see the plot .

A small number of pointing data (N=14) were recorded immediately after the installation of the new track model, and the plots of the residuals is shown below left:

The strong trend of daz with elevation indicates an error in the azimuth encoder zero-point, and running the data through the FIT9 program to optimize the telescope model, suggested mainly a change in the zero-point of 35 arcseconds. With this and the other smaller changes made to the model, the data should look as shown above right.

The new telescope model, was installed at about 03:30 and was used successfully during second shift.