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BASE
LAS\BASE [Deg] [/PLOT [Ipen]] [/INDEX] [/OBS] [/CONTINUUM [flux]]
LAS\BASE SINUS Amplitude Period Phase [/PLOT [Ipen]]
LAS\BASE LAST [/PLOT [Ipen]]
When working on single spectra, BASE copies R into T, then subtracts
from R a polynomial baseline of degree Deg, or a sinusoidal baseline if
the first argument is SINUS. Zones defined by the SET WINDOW command are
not used to fit the baseline. The T content may be recovered with SWAP.
BASE SINUS Amplitude Period Phase
(Phase is in the same unit as the period, usually km/s or MHz) Subtract
a sinusoid. Minimization will be done including also a linear baseline
in addition to the sinusoid.
BASE LAST
Use the last determined baseline instead of computing a new one. It can
be useful to find a baseline from one backend and apply it to another.
This also applies for sinusoidal baselines.
BASE /PLOT
Plot this baseline after the minimization, using the Ipen-th pen proper-
ties. The pencil 2 (red at startup) is used by default.
BASE /INDEX
Subtracts a baseline to all records that have been loaded. This option
is not needed if SET ACTION INDEX. /PLOT and /INDEX options are incom-
patibles.
BASE /OBS
indicate that the baseline is to be fitted to the current R buffer ob-
servations. This option is not needed if the action level is OBS (de-
fault). /OBS and /INDEX are incompatible.
BASE /CONTINUUM
Divide the spectrum by the baseline rather than subtracting it and mul-
tiply by the average flux. This is useful to keep the continuum level,
when continuum is present and variations of atmospheric emission are
properly subtracted out by fast enough switching. This is of course the
case for correlation spectra (e.g. coming from an interferometer). The
continuum level will be adjusted to the value of the argument 'flux', if
present; e.g. /CONTINUUM 1.0 will produce a spectrum of line-to-continu-
um ratio. BASE /CONTINUUM does not work with BASE LAST or BASE SINUS.
Gildas manager
2011-09-07