6 USING PRIOR REDUCTIONS—CLONING

echomop provides easy access to facilities to enable previous reductions to be used as baselines for a current reduction. For example, the order traces may be in the same positions, the wavelength calibrations may be the same etc.

To include data from previously-created reduction databases the number of the option (in ECHMENU main menu) should be followed by a ‘<’ character indicating that the information which would otherwise be generated should be copied from a previous reduction file. e.g.:

2<source-file

would copy the order-trace data (created by step 2 of a reduction) from the reduction database source-file, instead of calculating the relevant values.

To invoke ‘cloning’ when using single-function tasks (e.g. ech_trace) set TUNE_CLONE to the name of the source reduction file. e.g.:

ech_trace tune_clone=source-file

this would accomplish the same as the ECHMENU example above.

This option is most useful for cloning arc line identifications, as Option 10 (wavelength calibration) will automatically detect any global shift and re-identify the lines using the previous identifications as a template. To use the facility for this, the following sequence of options should be used: