  Long slit spectra of the region around the Luminous Blue Variable AG Car
obtained in June 1990, just before the onset of its new brightening phase,
indicate that AG Car was in the hottest phase so far recorded. The spectrum
shows strong broad emissions of He II 468.6 nm, and [Fe III] 465.8-470.1 nm,
and He I, N II, Si III, Al III and Fe III with a P Cygni profile. We have also
identified weak lines of C II and O II. A faint continuum emission has been
detected within the whole ring nebula. We also find that the spectrum of some
regions is partially due to scattered star's light. This provides evidence of
the presence of dust grains, and indicates that even in present times dust is
condensing from AG Car wind. The sharp outer edge of the ring suggest the
presence of a shock front. We have also identified an extended low density H II
$halo$, which should be associated with the residual of the stellar wind of a
previous cooler evolutionary phase of AG Car. In the halo the H$\alpha$/[N II]
ratio is strengthened with respect to the ring nebula, possibly because of a
discontinuity in the N abundance. We suggest that part of the star's reddening
originates in the ring nebula and diffuse halo, which could alter the present
estimates of the star's distance. The extracted spectrograms are available as
computer files on request to<EMAIL_ADDRESS>Article in press in A\&A.
