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Pointing
990729 report

Pointing with the new Telecope Control Software


SUMMARY
Tracking of Jupiter was done using the new TCS, and at this level seems to have done so successfully.


Jupiter is not an ideal pointing source, being so large, so the results probably only show that the TCS is performing well. The offset between the Jupiter data and the one very low elevation point on the much smaller Venus indicates a systematic error in the Jupiter data from the expected collimations, which detracts further from its usefulness for this purpose. Anyhow, allowing all of the 7 parameters of the telecope model to vary in order to minimize the residuals produces the 'fit' below :

The azimuth residuals are now nicely randomized, although the same cannot be said for the elevation residuals, probably indicating that the data are unsuited for the purposes of updating the model. The suggested changes to the model are shown below, although the large change in parameter #6 - the elevation zero-point - is just a reflection of the systematic elevation error on Jupiter mentioned above :

 PT990729C.DAT 
 model #   490
 RXB  
 No. of points  = 101

  N           OLD    FIXED=1      +          +            NEW

  1          11.2       0        0.0       -2.5           8.7
  2          17.8       0        0.0       -1.1          16.7
  3          50.9       0        0.0        7.7          58.6
  4         158.8       0        0.0        1.8         160.6
  5   229 55 26.1       0        0.0       11.3   229 55 37.4
  6   351 19 21.5       0        0.0      -21.5   351 18 59.9
  7         -13.1       0        0.0       10.6          -2.5
  8           0.0       1        0.0        0.0           0.0
  9           0.0       1        0.0        0.0           0.0
 daz =   0.0 +-  1.6     del =   0.0 +-  2.1     vec =   2.2 +-  1.4

The offset in elevation between Jupiter and Venus persists, but this exercise may still suggest that the model may need improvement and that a more appropriate dataset be obtained for that purpose soon.

Primarily, there is no evidence that the TCS is handling the pointing or track models in any way incorrectly.


Iain Coulson
29 July 1999
Contact: Iain Coulson. Updated: Sat Nov 6 18:00:31 HST 2004

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