2 Observations and data reduction

We have obtained three spectra of V589Sgr at the Danish 1.54 m telescope on La Silla on May 29/30, 2000, with DFOSC grism #15 (HJD 2451694.6583), grism #5 (HJD 2451695.6228) and grism #7 (HJD 2451695.6422). These grisms have resolutions of 13, 7.5 and 4 Å, and yield a combined spectral range of 3800-9500 Å. Reductions were done in the usual manner using standard IRAF routines. The spectra were flux-calibrated with the standard stars LTT3864 and LTT7987 (Hamuy et al. 1992; Hamuy et al. 1994). To minimize slit losses and improve flux calibration, a wide slit was used for standards stars (5 $^{\prime\prime}$) while the slit for all objects was aligned along the paralactic angle. The wavelength calibration functions were constructed with $\approx$40 He-Ne lines and had typical $\rm rms$ of 0.1 Å.

Figure 1: Spectrum of V589 Sgr obtained with DFOSC grism #15. Main emission lines are labeled. The H$\alpha$ flux is truncated in the lower panel (the maximum is at 3.1 10-14 erg s-1 cm-2 A-1) in order to better view all other features