How
to Use the Spectroscopic Quick Tool
1).
Open a MIDAS session in the wg5off machine :
> inmidas
2).
Create a
catalogue of images you want to reduce.
Go
to the directory where the data are.
midas> cd /data/raw/YYYY-MM-DD
Create an image catalogue with the frames you want to reduce:
midas>
cre/icat target ONTT*.fits
Edit
this catalogue target.cat using
emacs or vi
or whatever, and select only the files you needs, the object frames of
one target.
3).
Arc:
If
you have an arc
corresponding to your data, good. For a simplier use you can rename it
(ex: arc_B.fits). This
file will be use for the
reduction, to do the wavelength calibration of the spectra.
If you don't have arcs, the procedure will go to look for
one in the sofi database.
4).
Flats:
**
If you don't have flat files: the
procedure will go to find some in the sofi database.
** If you have reduced flats, you just have to use the name of the
normalized flat (ex: flat_spectro.fits
or flat_spectro.bdf).
** If you have the flat frames :
- you can use the
SOFI_spectroflat procedure to reduce them.
- you can just create an image
catalogue with the names of the frames,
midas> cre/icat flat ONTT*.fits
Edit
this catalogue
flat.cat and select the 4 frames corresponding to your set
up. This
catalogue flat.cat
will be
used as input for the spectroscopy reduction procedure.
5).
Standard star:
If
you want to divide
your data by a standard star,
and if you have data of a standard star:
Reduce
the standard star with the
SOFI_spec_redu.prg procedure
putting the last parameter equal to n (for none).
You
will have output files
corresponding to your reduced
standard star : final_spectrum.tfits
and final_spectrum.fits.
Rename
them standard_spectrum.tfits
and standard_spectrum.fits,
and use the tfits file as input to the spectroscopy reduction procedure.
If you don't
want to divide by a standard star, just use "n" as input.
6).
Run the sofi_spec_redu.pg procedure :
midas> @@ sofi_spec_redu
target.cat arc.fits flat.cat
standard_spectrum.tfits
or
midas>
SOFIRE/NTT target.cat arc.fits flat.cat
standard_spectrum.tfits
or
midas> @@ sofi_spec_redu
target.cat arc.fits
flat_spectro.fits
standard_spectrum.tfits
If
you don't want to divide by the
standard star :
midas>
@@ sofi_spec_redu target.cat arc.fits flat.cat n
If
you don't have flat :
midas> @@ sofi_spec_redu
target.cat arc.fits n n
If
you don't have arc:
midas>
@@ sofi_spec_redu
target.cat n n n
Of
course, you can combine any of
these solutions.
At
the end, you will have:
*
final_sepctrum.fits and final_spectrum.bdf : the image
of the final spectrum
*
final_spectrum.tfits : the table of the final spectrum. That the
useful file. This table can be read inside midas using the
command :
midas> read/tab final_spectrum.tfits
You have 3
columns :
-- X_coordinate : wavelength
-- Extracted_spectr
:
Spectrum of your object
-- Sky_spectrum : spectrum of
the sky
You can plot the
results using the plot/tab command:
midas>
plot/tab final_spectrum.tfits :X_coordinate :Extracted_spectr
[ In fact the
result is automatically plotted inside the graphic
window. ]
*
final_spectrum_status.ascii :
an ascii file with the log of the procedure.
* final_spectrum_aver_i
:
the images of the recombinations
* final_spectrum_diff_i
:
the images of the differences
In
summary, the quick tool to reduce SOFI data does :
- prepare the
frame to be treated by isaacp (some keywords are added,
some are changed to be understandable by isaacp).
- calibration in
wavelenght using isaacp wavecal over the arcs.
- division of
the science images by the flat.
- run isaacp
sw_spjitter to simply do the reduction ! for more
information have a look onto the help of isaacp sw_spjitter.
- plot the final
spectrum for verification.