Introduction to Portable--CGS4DR

The fourth generation COOLED GRATING SPECTROMETER, CGS4, is designed to operate on UKIRT in the 1--5 m region of the electromagnetic spectrum at resolutions in the range / 300--20000 (Mountain et al. 1990, Ramsay 1993). To reduce background noise, it is maintained on the telescope in vacuum at cryogenic temperatures. It achieved first light at UKIRT on 4 February 1991 (Carswell et al. 1991). On 22 April 1995 a new InSb 256 256 array was commissioned into the instrument. The new array having a dark current of << 1 and a read noise of 40 per integration, is much more sensitive than previous detectors. On any given spectroscopic night, an observer can expect to acquire and reduce 100 Mb of high quality data with CGS4.

To an observer, the system appears as two black boxes: the data acquisition system and the data reduction system (Wright et al. 1994). Both are under the direct control of the observer and can be manipulated to deal with a wide variety of astronomical configurations. The data is, therefore, both acquired and reduced in real-time at the telescope.

This document describes the CGS4 data reduction system now called Portable--CGS4DR. The software has been carefully designed and tested under the Figaro (Shortridge 1993) and ADAM (Lawden & Hartley 1992) environments under Unix. The data files produced by Portable--CGS4DR are readable by standard Figaro applications although not all may handle the quality and error arrays correctly.

For best results, Portable--CGS4DR should be run on a single user workstation having at least 32 Mb of main memory and a colour monitor. It can, of course, run on a dumb terminal and display to any STARLINK supported graphics device.

If you think you have discovered a bug, please report it by e-mail to usscstar.rl.ac.uk.