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This section briefly describes the on-line operation of the FEROS
software at the ESO 1.52m telescope. For a full documentation of FEROS
see:
http://www.ls.eso.org/lasilla/Telescopes/2p2T/E1p5M/FEROS/docu/pages/frames.html
The FEROS on-line DRS allows a complete reduction of the science
spectra taken during the night from the CCD system. The on-line DRS
is based on the MIDAS context feros.
To install the on-line software after the DRS is installed, the MIDAS
programs of the directory
$MIDASHOME/$MIDVERS/stdred/feros/locproc
have to be copied to the local midwork directory.
After CCD readout, the BIAS program
- includes the status
informations from the CCD, the Telescope Control System (TCS), and the
Instrument Control System (ICS) in the FITS header
- transfers the
2-D spectra to the instrument workstation (IWS) if the remote
autosave is turned on (BIAS command remsave+).
- starts
on the IWS the MIDAS programm @@ loadccd fero [filenum]
where filenum is the running 4-digit filenumber of the
CCD frame.
The loadccd program itself
- loads the frame fero[filenum].mt into the display,
- adds the incoming file to the catalogue Feros.cat,
- writes the FITS file to the DAT drive /dev/rmt/1mn (BS 2880)
- starts the automatic reduction via
- @@ autoreduce fero [filenum]
According to the four possible exposure types (FLATFIELD, CALIBRATION,
DARK, and SCIENCE) given in the descriptor EXPTYPE, the autoreduce
program starts the following actions:
-
FLATFIELD: adds the incoming file to the catalogue FF.cat
-
CALIBRATION:
adds the incoming file to the catalogue ThAr.cat
-
DARK:
adds the incoming file to the catalogue Dark.cat
-
SCIENCE:
- adds the incoming file to the catalogue Objects.cat
- start the pre-reduction of the the file
(@@ prered [filenum] raw_image)
where raw_image is the name of the input file for the
following on-line reduction.
- computes the barycentric velocity according to the telescope
position and writes the result to the descriptor BARY_CORR
- computes and subtracts the interorder background of the echelle
spectrum (BACKGR/FEROS)
- extracts the echelle orders (RECTIFY/FEROS, EXTRACT/FEROS)
- removes the blaze function and the pixel-to-pixel variations
(FLAT/FEROS)
- rebins the echelle orders to wavelengths (REBIN/FEROS)
according using pre-determined dispersion coefficients.
In this step also the barycentric correction is applied.
- merges the echelle orders (MERGE/FEROS) into two 1-D
spectra named f[filenum]1 and f[filenum]2
where the spectrum with the ending 1 refers to the spectrum
recorded on the object fiber and the spectrum with the ending 2
to the spectrum recorded on the sky/calibration fiber.
This standard reduction is controlled by the FEROS context keywords
which can be listed together with their current contents by the
command SHOW/FEROS and are set with the command SET/FEROS key=[value].
See below for useful keywords to be used during the observing session.
Next: Initialization of the DRS
Up: FEROS
Previous: Description of FEROS keywords
Petra Nass
1999-06-15