Pointing
Heterodyne pointings in November & December 2005 were rather few due to the extensive use of AzTEC at the JCMT, and so this analysis is the latest since that of 09 Nov 2005 and covers the period from the end of the bulk of the AzTEC observing through until the shutdown on 13 Feb (or, rather, until 08 Feb, when the engarchive record of leg temperatures etc ceases).

The plots below show the pointing data for, respectively, RxA & RxB ;

There are no noticeable systematics (pointing model term errors), and the rms errors are roughly as before.

Thermal - analyses of the elevation residuals as functions of Receiver and antenna leg temperatures:

  FE  No.of data   fit                              Temp range
  --  ----------  ----------------------------     -----------
   A      36      del = (-1.21 +- 2.41)*T_diff     -0.9 to -0.1
                      = (+0.16 +- 0.40)*T_mean      1.5 to  5.5

   B     220      del = (-2.07 +- 0.38)*T_diff(**) -1.0 to +2.0
                      = (-0.53 +- 0.06)*T_mean(**)  -4  to  10

The last two relationships are very significant and are shown below:

The trend -vs- T_mean is somewhat stronger than that -vs- T_diff. The sparse RxA data shed no light on their universality. They imply that the relevant thermal terms in the model (TEMP_SLOPE and TEMP_MEAN_SLOPE) will need checking and adjusting during or following the Functional CheckOut of the telescope (July ? 2006).

Focus

      FE  axis  No.obs.    mean   s.d.  Notes ('significant' trends)
                           (mm)   (mm)
    ----- ----  -------  ------- ------ -----------------------------
     RxA    Z      23     -0.03   0.08                 0 to 6      
            X      14     -0.05   0.21     
            Y      16     +0.28   0.16

     RxB    Z      97     +0.07   0.10   1
            X      42     +0.26   0.16   
            Y      43     +0.20   0.15

                                                       T-range
   Notes : 1 : Z_RxB = (-0.017 +- 0.003)*T_leg        -4 to 10

The one statistically significant trend is not of great amplitude (although weakly supported by the RxA data for the same period), but is contrary in sign to that seen last time. The change made to DZT_COEFF last time may need reversing !