Multi-object Spectra

Although ECHOMOP was produced for the reduction of data taken with the UCLES Echelle Spectrograph, it is in no way limited to processing data from this particular instrument, or even, to data from echelle spectrographs. The package can equally well be used on multi-object spectra obtained, for example, using the popular fibre based instruments. If you are processing this type of data the following points need to be remembered.

Each spectrum will need to be independently wavelength calibrated as the expected inter-order relationship checked for by completely automatic calibration will not be valid. Automatic identification of lines will however, still be possible on an object-by-object basis and if all the spectra have the same range (in wavelength), then the wavelength limits obtained on successfully calibrating the first object can be used as constraints for the others. In this instance the ech_idwave option/task would be run interactively for the first object, and then via a command such as the example below (for object 2), for all the remaining objects.

    % ech_idwave IDX_NUM_ORDERS=2 \
                 ARC=THAR ECH_FTRDB=ARCDIRS:THAR \
                 ID_INTERACT=NO \
                 ...other parameter settings...\
                 MIN_WAVE=3250. \
                 MAX_WAVE=3295. \
                 NOPROMPT