Bad weather kept us closed until about 02:00 MDT.

During preflight checks, we had a recurrence of the secondary E actuator failing to finish its 
move on a full step, so that the collimate process reported errors.  We homed the E actuator 
(the position error was 1), which solved the problem.  We moved the mirror arround at various
altitudes and could not reproduce the error.  The PR (2560) was updated.  

We opened under partly cloudy skies at ~02:00 and tested the pointing model installed during
shakedown.  We focused to 1.7" FWHM images with ~10 per cent asymmetry (11.7 pixels vs. 10.2 
pixels), which is fair under gusty east winds.  The out of focus images showed more signs of
a small collimation error but the cone fans were only turned on when we opened, so it is 
probable the primary was not yet in thermal equilibrium, and with variable seeing anyway, 
it was not worth trying to improve the collimation at this time.  

We observed a 20-point grid (TGRID:GRID_5_4_25_80_T_30.DAT).  It was clear during the 
observations that the errors in target position in the engcam images were large.  When we
used tpoint to calcuate the mean error between the observed and fitted positions using the model 
obtained on 2001/08/06 (tdat:telmod.dat;20).  Fitting the points we obtained tonight to this 
model gave an rms error of over 10 arcsec, with all the error vectors pointing east-west.  

When we allowed all parameters to vary, we got a 2.6 arcsec rms error.  The largest change in 
parameters from the old fit was in AW (azimuth axis west tilt), which moved closer to zero but 
with opposite sign:

       coeff       change     value    sigma

  1     IE         -0.119   -185.37    2.759
  2     IA         -8.339   -268.02    2.566
  3     AN         -0.432     -8.97    0.894
  4     AW        +12.095     +4.98    0.825
  5     HWCA2      +2.323     +2.54    1.164
  6     HWSA2      +1.133     +1.20    1.270
  7     HNCA1      +1.651     +0.92    1.471
  8     HNSA1      -1.821     -2.67    1.429
  9     CA         +4.141    +21.97    1.878
 10     PZZ1       +5.212   -121.24    7.593
 11     ACEC       +1.956     +4.86    1.514
 12     ACES       +0.301     -2.00    1.487
 13     TX         -2.531     -8.31    3.258

Sky RMS =   2.58
Popn SD =   4.59

We found this very surprising: what changed in the six days since the last model?  We repeated
the observations again, as we were worried we had made a mistake in rotator mode or in clearing
initial offsets, but obtained almsot identical results.  So, we implemented our new (sparse
20 point) model, then observed a different grid (TGRID:GRID_6_4_27_87_T_0.DAT), and it was
immediately obvious that the new model was getting much smaller errors.  
We generated tdat:telmod.dat;21