ECH_IDWAVE

Function

Summary

The routine allows selection of the major optional operations during wavelength calibration. Options are presented in a menu form and selected by typing a one- or two-character string, followed by carriage return. The following options are supported:

• AI (automatic identification), initiates a search and match of the feature database. Any preset limitations on the wavelength and dispersion range will be taken into account. When a solution is found, a report of probable status is made and the options to investigate the solution further (I), or search for further solutions by re-selecting (AI) are available.

• AF (automatic polynomial fitting), performs a cycle of fitting polynomials to identified lines, then clipping away any badly-deviant lines, and re-fitting, etc. Fitting ceases when a stable set of identified features remains.

• E (exit), leaves the line-identification menu and updates the reduction structure copy of the wavelength polynomial to reflect the latest calculated fit.

• F (fit), does a single-shot polynomial fit to the currently identified lines. A report of deviations is generated but no automatic clipping of deviant lines is performed.

• H (help), provides interactive browsing of the relevant sections of the help library for line identification.

• I (interactive identification), enters the interactive line specification/examination section. This section provides features for addition/deletion/re-fitting/listing etc of identified lines.

  A typical interactive plot appears below.

  

• IM (import ECHARC data), is used to provide an interface to the ECHARC arc line identification program. In general the XP option would first be used to export data for ECHARC processing. ECHARC would then be run, and finally the data IMported back into this package.

• O (order selection), is used to change the currently selected order when operating manually. The order number to be selected is prompted for.

• P (polynomial degree), is used to alter the degree of polynomial to be used for the wavelength fitting. This may vary up to the maximum specified by the parameter TUNE_MAXPOLY.

• XP (export data for ECHARC), is used to provide an interface to the ECHARC arc line identification program. In general the XP option would first be used to export data for ECHARC processing. ECHARC would then be run, and finally the data IMported back into this package.

Available Topics