1 Introduction

 1.1 What is Figaro?
 1.2 This document
 1.3 History

1.1 What is Figaro?

Figaro is a general-purpose data reduction package. Many people find it ideal for reducing spectroscopic data, but it also has powerful image and data cube manipulation facilities. The package was developed by Keith Shortridge, originally at Caltech and later at the Anglo-Australian Observatory (AAO). The version described here, Portable Figaro, is released and supported by Starlink.

Portable Figaro can be run in a command-oriented way from the Unix shell (usually a shell similar to the C shell). There is a second command line interface, ICL, from which Figaro can be run. ICL has some advantages over Unix shells, because it has floating point variables and can communicate with the ADAM parameter system that underlies Portable Figaro. ICL also avoids a lot of quirks in command syntax due to Unix shell meta-characters.

By default Figaro accesses data files in Starlink’s NDF data format. However, it can also access a number of different data formats, including Figaro’s old DST format, FITS and IRAF. Most Starlink packages can access the same range of data formats, and consequently Figaro can inter-operate with them. Earlier versions of Figaro supported a different and more restricted range of data formats. The current facilities are available in Portable Figaro version 5.1 and higher.

From version 5.3, Portable Figaro incorporates the Specdre package, which is used for spectroscopy data reduction and analysis. It includes cube manipulation, arc line axis (wavelength) calibration, re-sampling, and spectral fits.

From version 5.5, Portable Figaro incorporates the Twodspec package, which is used for longslit spectroscopy data reduction and analysis. It provides tools for calibration/correction of data and fitting of 2-D longslit arrays, either automatically or as an interactive process. These tools also offer a number of options for generating hard copy output of the resulting fits.

1.2 This document

This text largely dates from a complete re-write of the user documentation of Portable Figaro to accompany version 5.2 of Figaro. The style of this document is now more that of a cook book. It tries to offer novice users an easy entry into using Figaro whilst providing sufficiently detailed information for experienced users.

The main body of the document contains only a few cross-references between sections and references to other documents. References to external documents are provided as pointers to further information and need not be consulted to follow the examples in this manual. There is a keyword index, which should give you a quick way to find the information needed. The index contains references into this, and to other documents.

Section 2 is the starting point for new Figaro users; it outlines the basics, getting started, and gives some simple examples.

Section 3 contains information which can be applied in many Figaro reductions. There are details of parameter usage, the underlying data system, and access to foreign file formats. There is also an introduction to error-propagating tasks in Figaro.

Section 4 gives cookbook style details of a range of problems which can be addressed using Figaro: treatment of flat fields; B-star calibration; handling filters; flux calibration; fast Fourier transforms; removal of S-distortion; wavelength calibration; correction for extinction; and Gaussian fitting.

In Appendix A there is a classified list of Figaro commands.

In Appendix B there is a description of the features available with Specdre.

In Appendix C there is a manual for the Twodspec commands.

1.3 History

This document developed from the documentation for VAX/VMS Figaro, written by Keith Shortridge. It included some separate documents by J.G. Robertson, Jeremy Walsh and William Lupton. Appendices B and C are adapted from the Specdre and Twodspec manuals respectively.

Portable Figaro has evolved from Figaro 3.0 as distributed for VAX/VMS by Starlink, with some minor contributions from Sun Figaro 2.4.5 as produced by Samuel Southard (Caltech).

Figaro 3.0 was a release from AAO, but it had been adapted somewhat by Starlink (Figaro 3.0-3 and 3.0-5). Also some modifications had been made under the term ‘National Figaro’ (3.0-1 through 3.0-6). Porting Figaro 3.0 to Unix was a joint effort by the ‘Figaro Port Group’ Michael Ashley and Brad Carter (UNSW), Stephen Meatheringham MSSSO), Horst Meyerdierks (UoE, Starlink), and Keith Shortridge (AAO).

Specdre was written by Horst Meyerdierks (UoE, Starlink). It was incorporated into Figaro by Anne Charles (RAL, Starlink).

Twodspec was written by Tim Wilkins (Manchester and Cambridge) and Dave Axon (Manchester) with subsequent porting by John Palmer (Manchester) and Anthony Holloway (Manchester).