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.help lcalib Mar92 noao.onedspec
.ih
NAME
lcalib -- List information about the spectral calibration data
.ih
USAGE
lcalib option star_name
.ih
PARAMETERS
.ls option
Chooses calibration data to be listed. Option
may be: "bands" to list the bandpasses at each wavelength, "ext" to
list the extinction at each wavelength, "mags", "fnu", or "flam"
to list the magnitude, or flux of
the star (selected by the star_name parameter) at each wavelength, or
"stars" to list the star names available in the calibration directory.
.le
.ls star_name
Selects which star's magnitude list is chosen if the option parameter
is "mags", "fnu", "flam", or "bands". Also if '?' a list of available
stars in the specified calibration directory is given.
.le
The following three queried parameters apply if the selected calibration
file is for a blackbody. See \fBstandard\fR for further details.
.ls mag
The magnitude of the observed star in the band given by the
\fImagband\fR parameter. If the magnitude is not in the same band as
the blackbody calibration file then the magnitude may be converted to
the calibration band provided the "params.dat" file containing relative
magnitudes between the two bands is in the calibration directory
.le
.ls magband
The standard band name for the input magnitude. This should generally
be the same band as the blackbody calibration file. If it is
not the magnitude will be converted to the calibration band.
.le
.ls teff
The effective temperature (deg K) or the spectral type of the star being
calibrated. If a spectral type is specified a "params.dat" file must exist
in the calibration directory. The spectral types are specified in the same
form as in the "params.dat" file. For the standard blackbody calibration
directory the spectral types are specified as A0I, A0III, or A0V, where A
can be any letter OBAFGKM, the single digit subclass is between 0 and 9,
and the luminousity class is one of I, III, or V. If no luminousity class
is given it defaults to dwarf.
.le
.ls extinction
Extinction file. The current standard extinction files:
.nf
onedstds$kpnoextinct.dat - KPNO standard extinction
onedstds$ctioextinct.dat - CTIO standard extinction
.fi
.le
.ls caldir
Calibration directory containing standard star data. The directory name
must end with /. The current calibration directories available in the
onedstds$ may be listed with the command:
.nf
cl> page onedstds$README
.fi
.le
.ls fnuzero = 3.68e-20
The absolute flux per unit frequency at a magnitude of zero. This is used
to convert the calibration magnitudes to absolute flux by the formula
Flux = fnuzero * 10. ** (-0.4 * magnitude)
The flux units are also determined by this parameter. However, the
frequency to wavelength interval conversion assumes frequency in hertz.
The default value is based on a calibration of Vega at 5556 Angstroms of
3.52e-20 ergs/cm2/s/hz for a magnitude of 0.048. This default value
is that used in earlier versions of this task which did not allow the
user to change this calibration.
.le
.ih
DESCRIPTION
LCALIB provides a means of checking the flux calibration data. The calibration
data consists of extinction, bandpasses, and stellar magnitudes.
The extinction is given in an extinction file consisting of lines with
wavelength and extinction. The wavelengths must be order in increasing
wavelength and the wavelengths must be in Angstroms. There are two
standard extinction files currently available, "onedstds$kpnoextinct.dat",
and "onedstds$ctioextinct.dat".
The standard star data are in files in a calibration
directory specified with the parameter \fIcaldir\fR. A standard star
file is selected by taking the star name given, by the parameter
\fIstar_name\fR, removing blanks, +'s and -'s, appending ".dat", and converting
to lower case. This file name is appended to the specified calibration
directory. A calibration file consists of lines containing a wavelength,
a stellar magnitude, and a bandpass full width. The wavelengths are in
Angstroms. Comment lines beginning with # may be included in the file.
The star names printed by this task are just the first line of each file
in the calibration directory with the first character (#) removed.
The calibration files may be typed, copied, and printed. \fBLcalib\fR
may also be used to list data from the calibration files.
.ih
EXAMPLES
.nf
# List the extinction table
cl> lcalib ext
# Plot the extinction table
cl> lcalib ext | graph
# Plot the energy distribution
cl> lcalib mags "bd+28 4211" | graph
# List the names of all the stars
cl> lcalib stars caldir=onedstds$irscal/
# As above but for IIDS file
cl> lcalib stars calib_file=onedstds$iidscal/
.fi
.ih
REVISIONS
.ls LCALIB V2.10
This task has a more compact listing for the "stars" option and allows
paging a list of stars when the star name query is not recognized.
.le
.ih
SEE ALSO
standard, sensfunc, onedstds$README
.endhelp
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