2. Observations and data reduction
2.1. AAT visible spectral observations
Spectra of LSS 3184 were obtained during the nights of 1996 May 18 and 19 using the University College London Echelle Spectrograph at the 3.9-m Anglo-Australian Telescope. Exposure times were between 4 and 5 minutes. Standard IRAF packages were used for bias and flat field correction, reducing echelle orders to one dimensional spectra, and applying the wavelength scale using thorium-argon spectra. As the wavelengths covered by adjacent orders overlapped, the spectra covered the range 3850-5055 Å completely. The spectral resolution was . Velocity corrections for Earth's motion were found for each exposure using RVCORRECT and were applied using DOPCOR .
2.2. Hubble Space Telescope ultraviolet observations
Ultraviolet spectra of LSS 3184 were obtained using the Faint Object Spectrograph of the HST . Observations were made in RAPID mode using the blue detector, the square aperture and grating G160L over three orbits on 1997 February 7. Data files reduced using the most recent calibration files were downloaded from the HST archives on 1999 October 12. Individual exposures were made approximately 19.25 seconds apart. The usable part of the spectra covered the range 1150-2500 Å. Based on the ephemeris of Kilkenny et al. (1999), observations during the three orbits covered the phase () ranges from 0.3154-0.6099, 0.9327-0.2376, and 0.5602-0.8651, where maximumV magnitude is at and again at . Thus the star was observed by the HST over 85.5 per cent of its pulsational cycle.
© European Southern Observatory (ESO) 2000
Online publication: June 20, 2000