AIPS HELP file for WEIGHTIT in 31DEC26

As of Sat Jan 24 10:15:48 2026

HELP SECTION

WEIGHTIT
Type: Adverb  (scalar)
Use:  A code controlling the modification of data weights prior to
      their use in gain solutions and fringe fitting.  Weighting by
      uncertainty squared may be too extreme a method, down-weighting
      outer antennas excessively and producing failed solutions.
      Weighting linearly by uncertainty may be more stable.
      Values:
          0 - no change   weighting by 1/sigma**2
          1 - sqrt (wt)   weighting by 1/sigma may be more stable
          2 - (wt)**0.25  weighting by 1/sqrt(sigma)
          3 - wt -> 1.0   no weighting
Null value:  0
Tasks:
   BPASS.........Computes spectral bandpass correction table
   BPWGT.........Calibrates data and scales weights by bandpass
                 correction.  WEIGHTIT selects the bandpass, its square
                 root, or its fourth root.
   CALIB.........Determines antenna calibration: complex gain
   DGAUS.........Correct UV model for convolution by Clean beam
   FLATN.........Re-grid multiple fields into one image incl sensitivity
                 WEIGHTIT is used to down-weight outer pixels in each
                 facet.
   FRING.........Fringe fit data to determine antenna calibration,
                 delay, rate.
   KRING.........Fringe fit data to determine antenna calibration,
                 delay, rate.
   OMFIT.........Fits sources and, optionally, a self-cal model to uv
                 data.
   RLDLY.........Fringe fit data to determine antenna R-L delay
                 difference.
   SCIMG.........Full-featured imaging plus self-calibration loop with
                 editing.
   SCMAP.........Imaging plus self-calibration loop with editing.
Procedures:
   IMFRING.......Large image delay fitting with IM2CC and OOFRING.
   IMSCAL........Large image self-cal with IM2CC and OOCAL
   OOCAL.........Determines antenna complex gain with frequency-
                 dependent models
   OOFRING.......Fringe fit data to determine calibration with spectral
                 index options.
   PEELR.........Calibrates interfering sources in multi-facet imges.

EXPLAIN SECTION