1 Introduction

SPECX is a general mm and sub-mm wavelength data reduction system written by Rachael Padman at MRAO. At the time of writing the latest formally released version on the VAX is 6.2. However, pre-release copies of Version 6.3 are widely used. Branching off from the 6.3 VMS version, SPECX was ported to UNIX by Horst Meyerdierks of the Starlink Project and Rachael Padman. Remo Tilanus at JACH supplied the core routines to read GSD files and Tim Jenness at the JAC took over development for Version 6.7. The software version count on UNIX increased rather rapidly. 6.4 was the initial UNIX port of 6.3, but it existed only in beta-test versions. The first released version was 6.5, but it lacked the commands to read GSD files. Version 6.6 added support for GSD files. The current version on UNIX is 6.7 which added support for a new HDS map format (V4.2) and routines to aid the reduction of raster maps. Version 6.7 is currently supported by the Joint Astronomy Centre and distributed by Starlink.

Although SPECX may be used to process spectra obtained from many different instruments, Starlink users will find it particularly useful for the reduction of data obtained with the James Clerk Maxwell Telescope. SPECX has it’s own command line interpreter, and manipulates spectra on a pop-down stack. The package is designed to work on a variety of graphics terminals but is mainly used from within an X windows environment. Hardcopy may be output on a number of printers for which GKS drivers are provided by Starlink. In the UNIX version these are mainly different PostScript printers.

Some of the major features of SPECX are:

A thorough description of the package is given in the “SPECX Users’ Manual” which has been distributed as a Starlink Miscellaneous User Document (MUD/70). At the time of writing this MUD is available from Starlink for Version 6.3. No document has been prepared yet for the UNIX version, and the document on 6.3 is the closest approximation for UNIX users.

SPECX is intended primarily for the analysis of JCMT data and can read such data directly from the GSD files produced at the telescope. In the VMS version there are also facilities for reading data from a range of other important mm-wave telescopes, e.g. Onsala, FCRAO, UMASS CO survey, IRAM-FITS, JCMT RxG, NRAO 8-beam (see the SPECX user manual for details). Spectra and maps can be output as FITS files, Starlink NDFs, or ASCII files for reading into other packages.

This document concerns itself with the unix version of SPECX and will no longer discuss the VMS Version 6.2.