next up previous contents index
Next: MODIFY FREQUENCIES Up: MODIFY Previous: MODIFY FLUX   Contents   Index


        CLIC\MODIFY FOCUS [antenna1 value1 antenna2 value2 ...]

    Correct the phases for the offsets in focus, introduced to optimize  ef-
    ficiency. antenna1 is the antenna number, value1 the focus offset in mm,
    and so on.  The  phases  are  normally  corrected  in  real  time  since
    1996-nov-29.  Between 1996-may-29 and 1996-nov-29, the focus corrections
    were logged in the data files. Before 1996-may-29 they are only  in  the
    log-obs  files.  Between 1996-nov-29 and 1998-apr-02, the correction had
    wrong sign for the few projects using HIGH LOCK.

    So use MODIFY  FOCUS  with  NO  arguments  for  data  more  recent  that
    1996-nov-29:  this  should  correct  the  HIGH  LOCK  problem.   Between
    1996-may-29 and 1996-nov-29, MODIFY FOCUS with no arguments will use the
    focus offsets in the header and apply the corresponding phase offsets.

    For older data you may now search for the focus changes in the log files
    to apply the phase corrections before calibration; or use jumps  in  the
    phase calibration (SOLVE PHASE /BREAK) just as you had done before.

Gildas manager 2014-07-01