SOLVE FLUX

 

        CLIC\SOLVE FLUX [NOREFERENCE] [BEST n]

    Calculate the fluxes of the sources in the current index or the  antenna
    efficiencies  (Jansky  to  Kelvin)  if  the  source  flux is known.  The
    command can also be used to bootstrap source fluxes from a known source.

    It should be used before computing  any  amplitude  calibration,  on  an
    index  covering  a  reasonably  short  time  interval  to avoid possible
    efficiency variations.

    The commands should be used in the following way:

  - The command SET FLUX may be used to define the flux of one,  or  several
    of  the  sources  in  the  current  index  for  which the flux is known.
    Frequencies and dates may be specified in SET FLUX.  Alternatively,  the
    default  efficiencies  stored  in  the  data  header  will  be  used, if
    NOREFERENCE is present.

  - Then the  command  SOLVE  FLUX  will  use  the  sources  of  known  flux
    (optionally  with  matching  frequencies  and  dates)  to  determine the
    efficiencies for all antennas, and  compute  the  fluxes  of  all  other
    sources  using  those  efficiencies.  IF BEST n is present, the antennas
    giving the highest n fluxes will be used for  averaging  (n:  1  to  the
    number of available antennas).

    SOLVE  FLUX  now  gives  the  decorrelation  factor  relative   to   the
    efficiencies  logged  in  the  scan  headers (assumed to be the standard
    single-dish efficiencies).


  -  The command SHOW FLUX will give a list of fluxes either assumed or just
    determined.

  -  The command PRINT FLUX will create a procedure that may be  used  later
    to reload these fluxes in CLIC, if needed.

  -  The command STORE FLUX will store the fluxes  and  efficiencies in  the
    headers of the observations in the current index.

      SOLVE FLUX includes a correction for decorrelation effect,  using  the
    rms  phases computed from the 1-second integration dumps. Use SOLVE FLUX
    RAW to ignore this correction.

      SOLVE FLUX normally requires point sources to be meaningful. There two
    exceptions to this:
  -  Planets, at least the smallest ones.
  -  W3OH, a reasonably strong circumpolar HII region

    These sources  can  be  used  as  flux  calibrators.  Size  effects  are
    corrected  for  by  CLIC,  using the ephemerides to determine the planet
    characteristics, and a simple (but accurate) source model for W3OH.